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Dogs’ responses to visual, auditory, and olfactory cat-related cues
Accepted Manuscript Title: Dogs’ rto visual, auditory, and olfactory cat-related cues Author: Christy L. Hoffman Miranda K. Workman Natalie Roberts Stephanie Handley PII: DOI: Reference:
S0168-1591(17)30005-9 http://dx.doi.org/doi:10.1016/j.applanim.2016.12.016 APPLAN 4387
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7-4-2016 20-12-2016 31-12-2016
Please cite this article as: Hoffman, Christy L., Workman, Miranda K., Roberts, Natalie, Handley, Stephanie, Dogs’ rto visual, auditory, and olfactory cat-related cues.Applied Animal Behaviour Science http://dx.doi.org/10.1016/j.applanim.2016.12.016 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Dogs’ responses to visual, auditory, and olfactory cat-related cues
Christy L. Hoffman, Miranda K. Workman, Natalie Roberts, & Stephanie Handley
Department of Animal Behavior, Ecology, and Conservation Canisius College 2001 Main Street, Buffalo, NY 14208
Correspondence should be addressed to Christy L. Hoffman, Department of Animal Behavior, Ecology, and Conservation, Canisius College, 2001 Main St., Buffalo, NY 14208 Email: [email protected] Phone: (716) 888-2775
Highlights
We tested dogs’ responses to visual and auditory cat-related and control stimuli.
Dogs oriented more to the auditory cat stimulus than to the visual cat stimulus.
Dogs that had hurt small animals were more attentive to the auditory stimuli.
Responses to cat sounds might predict which shelter dogs will get along with cats.
Abstract Standardized assessments have been developed to assess dogs’ behaviors around other dogs, but there currently is no validated way to predict how a dog in an animal shelter will behave around cats, unless the dog’s previous history is known. This study explored dogs’ responses to visual, auditory, and olfactory cat-related and control stimuli, and tested whether dogs known to interact safely with cats and other small animals responded differently to the stimuli than dogs known to have injured or killed such animals. We video recorded 69 dogs’ responses to the stimuli, and raters who were blind to the dogs’ behavioral histories coded the dogs’ reactions. Dogs differed in the amount of time they spent orienting to the cat and control visual stimuli and sounds. They spent significantly more time orienting to the cat sound than to the visual cat stimulus, to the visual cat stimulus than to the visual control stimulus, and to the control sound than to the visual control stimulus (for all, p < 0.01). Dogs that were presented with the visual stimuli in conjunction with the cat odor (i.e., cat urine) sniffed the visual control stimulus more than cats in the non-olfactory condition (p = 0.04), but they did not sniff the visual cat stimulus more. Dogs that had killed or injured a cat or other small animal spent more time orienting to the cat sound than dogs that did not have this history (p = 0.01). The results indicate that dogs are more responsive to auditory than visual or olfactory cat-related stimuli, and that it may be possible to use cat sounds to predict which shelter dogs are likely to fare well in homes with cats or other small animals.
Keywords: dog; cat; perception; behavioral assessment; predatory behavior
1. Introduction According to the Association for the Prevention of Cruelty to Animals (ASPCA, 2015), 3.9 million dogs enter animal shelters in the United States, and 1.2 million are euthanized annually. Dog owners relinquish their dogs to shelters for a variety of reasons, but behavior problems are frequently cited as a motivating factor (Diesel et al., 2010; Kwan and Bain, 2013; Salman et al., 1998). A dog brought into a new home is expected to adapt to the owner’s lifestyle and household, which may include children, dogs, and cats in addition to multiple adult humans. Dogs that do not behave appropriately with household members are at risk of being relinquished to shelters (Neidhart and Boyd, 2002). When a dog does end up in a shelter, the shelter may use a behavioral assessment to determine whether, and under what conditions, the dog should be rehomed. Commonly used behavioral assessments include Assess-a-Pet (Sternberg, 2002), a modified version of Assess-a-Pet (Bollen & Horowitz, 2008), and Safety Assessment for Evaluating Rehoming™ (SAFER) (Weiss, 2007). Some behavioral assessments use stuffed or plastic dog models and toddler-sized dolls to predict how shelter dogs will behave around dogs and children (Barnard et al., 2011; De Meester et al., 2011; Dowling-Guyer et al., 2011; Reid and Collins, 2012). However, there is no validated assessment to predict how a dog will behave around household cats and other small animals even though dogs vary greatly in their tendencies to direct predatory behaviors toward such animals. The full canine predatory motor pattern is orient > eye > stalk > chase > grab-bite > kill-bite > dissect > consume, and the movement of prey triggers it consistently in
wolves (Coppinger and Schneider, 1995). Due to the dog’s role as a scavenger, the predatory motor pattern is more relaxed and variable in dogs than in wolves (Coppinger and Coppinger, 2001). Indeed, in successful livestock guarding dogs, the predatory motor pattern is either nonexistent or weak (Coppinger and Schneider, 1995; Coppinger and Coppinger, 2001). A dog’s breed may provide some insights into the likelihood of engagement in predatory behaviors. For instance, German short-haired pointers, miniature schnauzers, and Siberian huskies have historically played important roles as hunters or controllers of vermin, and they outscore other breeds on a measure of predatory chasing behavior (Serpell and Duffy, 2014). Environmental factors, however, particularly during early development, impact how strictly a purebred dog will follow breed-typical motor patterns (Coppinger and Schneider, 1995). Due to a lack of information regarding many shelter dogs’ previous experiences and the fact that most dogs that enter a shelter are mixed breeds (Salman et al., 1998), a shelter may be reluctant to adopt a dog to a home that includes cats or other small animals unless the former owner is able to provide a detailed history. Other shelters may resort to using live cats to conduct informal assessments of dogs’ behaviors around cats, but such assessments have not been validated and may be stressful and potentially harmful for the cats employed. Given that previous studies have shown that dog models and dolls do provide some indication of how dogs respond to living dogs and children (Barnard et al., 2012; Shabelansky et al., 2015), it is possible that a dog’s response to a cat model may predict how a dog will respond to cats or other small animals.
Previous research examining dogs’ responses to dogs and children have relied upon visual representations of dogs and small children even though the dog’s umwelt differs substantially from our own. Dogs’ eyes are incredibly sensitive to movement, but dogs do not see as well as humans during the day (Miller and Murphy, 1995). Compared to humans, however, their senses of hearing and smell are much more sophisticated. They can detect sounds up to 44,000 Hz whereas humans can detect sounds up to 17,600 Hz (Heffner, 1998), and dogs’ noses are 10,000 to 100,000 times more sensitive to odors (Walker et al., 2006). Because dogs’ auditory and olfactory abilities are so refined, assessments of dogs’ responses to children and animals might be improved by including olfactory and auditory components in addition to visual components. In this experiment, we tested dogs’ responses to visual, olfactory, and auditory cat-related stimuli. We hypothesized that dogs that had previously harmed or killed cats or other small animals would be more attentive to these stimuli than dogs that had not. In addition, we hypothesized dogs would be more attentive to the auditory cat stimulus than the visual cat stimulus and that dogs would engage more with the visual stimuli when they were paired with cat odors.
2. Methods 2.1 Participants We used survey-based data collected from dog owners in Western New York (United States) to select dogs for this study, which took place in the Animal Behavior Lab on the Canisius College campus in Buffalo, NY, USA. The online survey focused on
dogs’ behaviors around cats and other small animals. We sought a variety of dog participants, ranging from those that had killed or injured cats or other small animals to those that had never exhibited any harmful or predatory behavior toward cats or other small animals. Dogs selected to participate in the experiment were required to meet the following eligibility requirements: were current on their rabies vaccine; were older than 6 months old but younger than 9 years old; had experienced no surgery or orthopedic problems within the previous 12 weeks; and had resided with the current family for at least 6 months. Dogs with a history of aggression toward humans were excluded from participating. Only one dog per household was eligible to participate to ensure the dog participants were statistically independent of one another. A total of 69 dogs met the selection criteria. Forty-eight were male, and 21 were female. Three males and one female were intact. Fifty-four lived with cats at the time of the study. Dog participants were between 1 year and 8.5 years of age (M = 4.28, SD = 2.13). Ten percent of participants (n = 7) had lived in the household for 6 months to 1 year; 54% (n = 37) had for between 1 year and 4 years; and 36% (n = 25) had for more than 4 years. Fifty-eight percent (n = 40) had been acquired from an animal shelter or rescue or had been found as a stray, and 22% (n =15) had been acquired from a breeder. The remaining dogs came from a friend or family member (n = 7), a newspaper or online ad (n = 6), or a pet shop (n = 1). When asked about their dog’s breed, 41 participants only listed one breed, and 28 listed multiple breeds. Based on the first breed participants listed, the following is a breakdown of the number of dogs in the sample that belonged to each breed group: herding: 5, hound: 8, non-sporting: 5, sporting: 19, terrier: 15, toy: 9, and working: 8. For
more details regarding each dog participant, including owner-reported breed information, please refer to Table 1.
***Table 1 about here***
2.2 Stimuli Visual Cat Stimulus. The cat stimulus was an animatronic children's toy (Hasbro FurReal Friends Lulu Interactive Animated White Persian Kitty Cat, Hasbro, Pawtucket, RI, USA). When switched on, the cat blinked, swished its tail, moved its paws forward, rotated its head, moved its ears, meowed, and purred. Visual Control Stimulus. The control stimulus was a white, zippered pillowcase that contained a motorized ball (Bumble Ball, Otis and Claude, Union City, CA, USA) and plastic packing material. The pillowcase had two fabric eyes affixed to the end opposite the zipper. The pillowcase moved and vibrated when the Bumble Ball inside it was activated. Cat and Control Sounds. Auditory trials consisted of playing recordings of cat vocalizations and coins dropping. Each recording lasted 60 seconds. The recordings were edited from videos that were available on Youtube (www.youtube.com), and the sound files are included as supplementary files. The cat vocalization recording primarily included cats meowing but also included two cat growls. We chose to use the sounds of coins dropping as the control sound because they, like the cat sounds, occurred intermittently. In addition, there was variation in the sounds the coins made as they dropped, just as there was variation in the sounds the cats made. Each recording lasted
60 seconds and was no louder than 60 decibels. The cat and control sounds were transmitted through external speakers (Altec Lansing inMotion Speakers, Altec Lansing, New York City, NY, USA) attached to a laptop (Hewlett-Packard ProBook, HewlettPackard, Palo Alto, CA, USA). The laptop and speakers were in a room that adjoined the Animal Behavior Lab. The door between the two rooms remained open, although a baby gate kept dogs from entering this room. A custom-made 1.5m x 1.5m room divider blocked the laptop and speakers from the dog’s view. At the start of each trial, dogs were about 5 m away from the audio equipment. Cat Odor. In the olfactory condition, a polypropylene plastic tube that contained a piece of cotton soaked in cat urine was placed inside the cat and pillowcase. In the cat condition, the tube was taped to the cat’s battery compartment, which was located behind a layer of Velcro and fur on the underside of the cat. In the control condition, the tube was taped to the Bumble Ball that was zipped inside the pillowcase. The cap of the tube contained a hole so that the odor could escape. Each dog in the olfactory condition was exposed to odor from a single cat, although we used urine from eight different cats in the study. A local animal shelter provided the urine samples, which were expressed from cats prior to sterilization surgery. The samples were kept refrigerated until use, and we used the samples within one week of collection. The sexes and ages of the cats sampled are unknown. 2.3 Experimental Design Each dog experienced 6 novel stimuli, one at a time, in 6 separate trials and was randomly assigned to either an olfactory or non-olfactory condition. The first two trials included inanimate cat and control stimuli (visual); the second set of trials included
animate cat and control stimuli (visual); and the final set of trials included cat vocalizations and control sounds (auditory). We used random assignment to determine whether each dog experienced cat or control stimuli first within each set of trials. Thirtyfive dogs were presented with cat stimuli before control stimuli within each set of trials, and 34 were presented with control stimuli first. To prevent the laboratory from becoming contaminated with cat odors and interfering with the non-olfactory condition, all dogs assigned to the non-olfactory condition (n = 36) participated in the study before dogs assigned to the olfactory condition participated (n = 33). The dogs and owners selected for the study came to the Animal Behavior Lab for a visit lasting 30-45 minutes. Figure 1 illustrates how the lab was arranged for the study. Upon the arrival of the dog and owner, the experimenter attached a 6m long line to the dog’s collar or harness, and we removed the dog’s regular leash and any equipment that was aversive and/or impeded movement. The dog had 5 minutes to familiarize himself/herself with the experimenter and setting. The dog’s owner held the long line during the first 2 minutes of exploration, and a member of the study team (CH or MW) held the long line during the latter 3 minutes so that the dog’s owner could take a seat behind an exercise pen in the front, left corner of the lab and the dog could acclimate to the handler. We used two high definition video cameras (Panasonic HC-V720, Panasonic, Kadoma, Osaka Prefecture, Japan) to film the dog from 2 camera angles the entire time he/she was in the laboratory.
***Figure 1 about here***
Following the acclimation period, the handler walked the dog behind a custommade 1.5m x 1.5m room divider and shortened the lead to restrict the dog’s ability to move or see beyond the room divider. A research assistant then entered the lab and placed either the cat or pillowcase on a marked position 3m in front of the divider. The room divider prevented the dog from seeing the research assistant or prop during the set-up period that preceded each visual trial. After placing the study prop, the research assistant returned to the adjoining room so that she could remain out of the dog’s sight during the visual trials. Once out of sight, the research assistant announced the trial number, signaling the dog’s handler that the dog could move out from behind the room divider and approach the prop. Once the handler allowed the dog to move out from behind the room divider, the dog had 75 seconds to investigate the stimulus, upon which time the research assistant announced the end of the trial and the handler guided the dog back behind the room divider. Once the dog was behind the room divider and so could not see the research assistant or study props, the research assistant removed the first inanimate stimulus and replaced it with the other inanimate stimulus. As in the first trial, the dog’s response to the second inanimate stimulus was recorded for 75 seconds. The animate cat and control trials followed the inanimate trials and were performed in the same manner. The 75-second trial length was determined based on pilot testing of dogs’ responses to the visual cat and control stimuli. At the start of the sound trials, which immediately followed the animate trials, the dog sat or stood on a marked spot in front of the room divider and the dog’s handler shortened the lead to restrict the dog’s ability to move beyond that spot. The room divider that blocked the speakers and laptop from the dog’s view also blocked the
research assistant from the dog’s view. Once the auditory trial started, the dog was allowed to move and investigate the sound. The trial was 75 seconds long, beginning when the sound started and ending 15 seconds after the sound terminated. Following the presentation of the first sound, the handler guided the dog back to the starting point, and then the second sound was presented. Typically, the inter-trial interval between each of the 6 trials was between 30s and 60s. During each trial, the handler held the leash loosely, only restricting the dog’s movement when he/she attempted to enter areas marked as out of view of both camera angles. The handler and the owner did not interact or make eye contact with the dog during the trials. Some owners were given the option of reading a magazine during the trials, and others chose to engage with their cell phones during this time. Sample videos of the visual and auditory trials have been included as supplementary files. 2.4 Ethical Statement Canisius College’s Institutional Animal Care and Use Committee approved the study prior to the onset of data collection. Dogs’ owners signed a consent form allowing their dogs to participate in the study and provided proof that their dog had an up-to-date rabies vaccine. 2.5 Measurements Two research assistants used Noldus Observer XT 11.0 to code behaviors observed during the first 60 seconds of each trial. Behaviors recorded included orienting to stimulus, which was defined as looking toward and appearing to focus on the stimulus for at least one second while the head did not move, and sniffing the stimulus, which was defined as frequent, short inhalations through the nose directed at the
stimulus while the dog’s nose was within 2 cm of the stimulus. Both observers coded 10% of the videos to establish interrater reliability, which we calculated using Cohen’s Kappa coefficients. Kappa ranged from 0.84 to 1.00, and the average was 0.92. The research assistants coded the videos blind to dogs’ histories with cats and other small animals, and to whether each dog was in the olfactory or non-olfactory condition. 2.6 Data Analysis Dependent variables examined in the analyses included the following: time spent orienting to stimulus and time spent sniffing stimulus. According to the Shapiro-Wilk test, the data were not normally distributed, and so we ran non-parametric analyses. We used Friedman’s two-way analysis of variance and pairwise comparisons to compare the amounts of time the dogs oriented to the visual cat stimulus, visual control stimulus, cat sound, and control sound. Mann-Whitney U tests were performed to examine whether the order of presentation of the visual and auditory stimuli influenced the amount of time dogs oriented to the stimuli; whether dogs in the olfactory and nonolfactory conditions differed in the amount of time they oriented to or sniffed the animatronic cat and visual control stimuli; and whether living with a cat or a history of harming or killing cats or other small animals influenced the amount of time the dogs oriented to the visual and auditory stimuli. Wilcoxon signed rank tests were used to compare how much time dogs oriented to the inanimate and animate cat and control stimuli and how much time dogs in the olfactory condition sniffed the cat and control stimuli.
3. Results
There was no relationship between breed group and the amount of time dogs spent orienting to any of the stimuli (for all, p > 0.05). Due to this and because visual identification of mixed breeds is not reliable (Olson et al., 2015; Voith et al., 2009), all dogs were grouped together in the analyses that follow. 3.1 Visual and Auditory Conditions Dogs spent significantly more time orienting to the animate visual control stimulus than to the inanimate visual control stimulus (Z = 2.36, p = 0.02), but dogs did not differ in the amount of time they oriented to the inanimate and animate cat stimuli (Z = -0.18, p = 0.86). Because dogs did not differ in the amount of time they oriented to the inanimate and animate cat stimuli, the remaining analyses of dogs’ responses to the visual cat stimulus and visual control stimulus will focus on the inanimate condition. Dogs differed in the amount of time they spent orienting to the visual cat and control stimuli and cat and control sounds (χ2(3) = 108.58, p < 0.001) (Figure 2). Pairwise comparisons indicated that the dogs spent significantly more time orienting to the cat sound than the control sound, to the cat sound than to the visual cat stimulus, to the visual cat stimulus than to the visual control stimulus, and to the control sound than to the visual control stimulus (for all, p < 0.01).
***Figure 2 about here***
Whether the visual cat stimulus was presented before or after the visual control stimulus did not affect how long the dogs oriented to the visual cat stimulus (Z = 0.88, p = 0.38). Similarly, there was no effect of order on how long the dogs oriented to the cat
sound (Z = 0.64, p = 0.52). Dogs oriented longer to the visual control stimulus if it was presented before the visual cat stimulus (Z = -1.97, p = 0.049). They oriented longer to the control sound if it was presented after the cat sound (Z = 2.84, p = 0.005). 3.2 Olfactory Condition There was no effect of olfactory condition on the amount of time the dogs oriented to the visual cat stimulus or visual control stimulus (cat: Z = 0.69, p = 0.49; object: Z = 1.75, p = 0.08) (Figure 3). Dogs in both the non-olfactory and olfactory conditions spent significantly more time sniffing the cat stimulus than the control stimulus (non-olfactory: Z = -4.29, p < 0.001; olfactory: Z = -3.47, p = 0.001). Dogs in the non-olfactory and olfactory conditions did not differ in the amount of time they sniffed the visual cat stimulus (Z = 1.17, p = 0.24). However, dogs in the olfactory condition sniffed the visual control stimulus significantly longer than dogs in the nonolfactory condition (Z = 2.09, p = 0.04).
***Figure 3 about here***
3.3 History with Cats and Other Small Animals There was no relationship between dogs that did and did not live with a cat and the amount of time they spent orienting to the visual cat stimulus (Z = -0.89, p = 0.38), visual control stimulus (Z = -0.19, p = 0.85), or control sound (Z = -0.68, p = 0.50). There was a nonsignificant tendency for dogs that did not live with cats to spend more time than dogs that lived with cats orienting to the cat sound (Z = -1.73, p = 0.08).
Four of the 69 dogs had killed or injured a cat, and 3 of those had also killed or injured another type of small animal. An additional 14 dogs had killed or injured at least one small animal but not a cat. Dogs that had and had not killed or injured a cat or other small animal did not differ in the amount of time they oriented to the visual cat stimulus (Z = -0.57, p = 0.57) or the visual control stimulus (Z = -0.08, p = 0.93) (Figure 4). Within the olfactory condition, there was no relationship between whether a dog had killed or injured a cat or other small animal and the amount of time the dog spent sniffing the visual cat stimulus (Z = 0.62, p = 0.56) or the visual control stimulus (Z = 0.09, p = 0.95). Dogs that had killed or injured a cat or other small animal, however, did spend more time orienting to the cat sound than did dogs that had not (Z = 2.52, p = 0.01), and there was a nonsignificant tendency for those dogs to spend more time orienting to the control sound (Z = 1.79, p = 0.07) (Figure 4).
***Figure 4 about here***
4. Discussion Dogs were more attentive to the visual cat stimulus than the visual control stimulus and the cat sound than the control sound. In addition, they attended more to the auditory cat stimulus than the visual cat stimulus. The latter findings parallel results from previous work that has shown that dogs respond more to dog sounds than to visual representations of dogs (Déaux et al., 2015). Dogs in the non-olfactory and olfactory conditions did not differ in the amount of time they spent sniffing the cat stimulus, but dogs in the olfactory condition spent more
time than dogs in the non-olfactory condition sniffing the control stimulus. This finding may provide insights into how dogs perceived the cat and control stimuli. If dogs viewed the visual cat stimulus as being cat-like, the associated cat urine smell in the olfactory condition would have been congruent with the dogs’ expectations about the stimulus; thus, the dogs did not need to spend more time investigating the cat stimulus in the olfactory condition than in the non-olfactory condition. The dogs’ increased interest in the control condition, however, may have been due to the cat odor being unexpected in the presence of the control stimulus; that is, the dogs’ interest may have been piqued by something that did not look like a cat but smelled like a cat. Previous work has shown that dogs look longer at stimuli when experiencing incongruent information from two sensory modalities. For instance, Adachi, Kuwahata, and Fujita (2007) reported that dogs looked longer at visual images of their owner if an audio recording of a stranger’s voice, rather than their owner’s voice, preceded the image. Although dogs that had and had not killed or injured a cat or other small animal did not differ in their responses to the visual stimuli, dogs that had such a history spent significantly more time orienting toward the cat sound than dogs without this history. In addition, there was a nonsignificant tendency for these dogs to spend more time orienting to the control sound. These findings indicate that dogs that have killed or injured cats or other small animals may be hypersensitive to auditory information, particularly if it sounds like cat vocalizations. Unfortunately, our sample included only four dogs that had killed or injured cats, and so we were unable to examine killing and injuring cats independently of killing and injuring other small animals.
We expected dogs would be more attentive to the animate visual cat stimulus than the inanimate visual cat stimulus because dogs are highly sensitive to movement (Miller and Murphy, 1995), yet dogs did not show more interest in the animate cat. There are a few possible explanations for this. First, due to study design constraints, the animate cat was always presented after dogs had been exposed to the inanimate cat. As a result, the novelty of the cat’s visual appearance may have dissipated prior to the animate cat trial. Furthermore, although parts of the cat moved during the animate condition, the cat did not walk or run. Had the stimulus exhibited more pronounced movements, we may have seen differences in dogs’ responses to the animate and inanimate cat stimuli. Although dogs showed more interest in the auditory trials than the visual ones, it is possible that the cat sounds did not sound quite like live cat vocalizations to the dogs studied. Dogs can hear frequencies that humans cannot (Heffner, 1998), and so recordings created for human ears may include high frequencies detectable to dogs but not to humans. Three pieces of evidence, however, suggest the dogs may have perceived the sounds as originating from cats. First, the dogs spent significantly more time orienting to the cat sound than the control sound. In addition, dogs spent more time orienting to the control sound when it followed the cat sound than when it preceded it, suggesting the cat sound may have heightened the dogs’ attentiveness to sounds. Finally, at the conclusion of their study visit, dogs were walked on leash through the room from which the experimental sounds were played, and as they passed through, numerous dogs engaged in intense sniffing behaviors and pulled on leash toward the
side of the room from which the sounds originated. One interpretation of this behavior is that the dogs were searching for and expecting to find cats. Cat urine affected dogs’ behavior in the visual control condition, but it is certainly worth questioning whether cat urine is the most ideal cat-related odor to present to dogs. Given dogs’ documented tendencies to sniff ano-genital regions when greeting other dogs and other species (Millot, 1994), dogs’ high level of interest in other dogs’ urine (Lisberg and Snowdon, 2011), and cats’ tendencies to employ urine marking as a way to communicate with other cats (Bradshaw and Cameron-Beaumont, 2000), it is certainly plausible that dogs learn important information about cats from odors contained in their urine. Dogs may have responded differently, however, had the visual stimuli included scent marks derived from glandular secretions from cats’ faces and tail areas in lieu of urine. Such secretions are thought to play an important role in cats’ intraspecific interactions (Feldman, 1994). Findings from this study suggest it may be possible to develop an assessment tool that uses cat sounds to predict whether a dog residing in an animal shelter will be successful if adopted into a household that includes a cat or other small animals. Such an assessment, however, may indicate some dogs should not be rehomed with cats even though they may, in reality, be fine with cats. Thus, it is important that any such behavioral assessment be used in conjunction with other sources of information about the dog's behavior, such as information provided by the owner at the time of surrender and by kennel staff and volunteers who routinely interact with the dog. The detailed reports that dog participants’ owners provided indicated that half of the dogs that had killed or injured a cat or other small animal resided with at least one cat at the time of
the study, and most of these dogs coexisted peacefully with household cats. As only four dogs in our sample had actually killed or injured a cat, more data are needed to determine if such dogs consistently orient more toward cat sounds than dogs without such a history. Furthermore, additional testing is needed to determine whether an assessment could specifically predict dogs’ responses to indoor cats because, as our survey data indicate (Hoffman and Workman, unpublished data), some dogs interact appropriately with cats when indoors but chase cats when outdoors. 5. Conclusion We tested dogs’ responses to visual, auditory, and olfactory cat-related stimuli and found that dogs were most attentive to the auditory stimulus. Dogs showed no more interest in the olfactory cat condition than in the non-olfactory cat condition, suggesting that dogs perceived the visual cat stimulus to be cat-like, regardless of odor condition. Furthermore, dogs that had injured or killed cats or other small animals were more attentive to the auditory cat stimulus than those that had not. Our findings indicate that it may be possible to use recordings of cat vocalizations to assess which shelter dogs are likely to fare well in a home with cats or other small animals.
Acknowledgements We are grateful to the owners of the participating dogs for completing the study survey and bringing their dogs to campus. We thank Colleen Bates and Raechel Crosby for their assistance with this project and two reviewers for helpful comments on the manuscript. This study was supported by a grant to CH and MW from the Association of Professional Dog Trainers Foundation, a grant to CH from the Al and Noura Gress Foundation, and by funding to SH and NR from the Canisius Earning Excellence Program.
Bibliography Adachi, I., Kuwahata, H., Fujita, K., 2007. Dogs recall their owner’s face upon hearing the owner’s voice. Anim. Cogn. 10, 17–21. ASPCA, 2015. Pet statistics [WWW Document]. ASPCA. URL https://www.aspca.org/animal-homelessness/shelter-intake-and-surrender/petstatistics (accessed 11.25.15). Barnard, S., Passalacqua, C., Capra, A., Marshall-Pescini, S., Previde, E.P., Valsecchi, P., 2011. Social behavioral profile of different dog breeds. J. Vet. Behav. Clin. Appl. Res. 6, 83–84. Barnard, S., Siracusa, C., Reisner, I., Valsecchi, P., Serpell, J.A., 2012. Validity of model devices used to assess canine temperament in behavioral tests. Appl. Anim. Behav. Sci. 138, 79–87. doi:10.1016/j.applanim.2012.02.017 Bollen, K.S., Horowitz, J., 2008. Behavioral evaluation and demographic information in the assessment of aggressiveness in shelter dogs. Appl. Anim. Behav. Sci. 112, 120–135. Bradshaw, J., Cameron-Beaumont, C., 2000. The signalling repertoire of the domestic cat and its undomesticated relatives. Domest. Cat Biol. Its Behav. 67–94. Coppinger, R., Coppinger, L., 2001. Dogs: A Startling New Understanding of Canine Origin, Behavior & Evolution. New York: Scribner. Coppinger, R., Schneider, R., 1995. Evolution of working dogs. Domest. Dog Its Evol. Behav. Interact. People 21–47. Déaux, É.C., Clarke, J.A., Charrier, I., 2015. Aggressive bimodal communication in domestic dogs, Canis familiaris. PloS One 10, e0142975.
De Meester, R.H., Pluijmakers, J., Vermeire, S., Laevens, H., 2011. The use of the socially acceptable behavior test in the study of temperament of dogs. J. Vet. Behav. Clin. Appl. Res. 6, 211–224. doi:10.1016/j.jveb.2011.01.003 Diesel, G., Brodbelt, D., Pfeiffer, D.U., 2010. Characteristics of relinquished dogs and their owners at 14 rehoming centers in the United Kingdom. J. Appl. Anim. Welf. Sci. 13, 15–30. doi:10.1080/10888700903369255 Dowling-Guyer, S., Marder, A., D’Arpino, S., 2011. Behavioral traits detected in shelter dogs by a behavior evaluation. Appl. Anim. Behav. Sci. 130, 107–114. doi:10.1016/j.applanim.2010.12.004 Feldman, H.N., 1994. Methods of scent marking in the domestic cat. Can. J. Zool. 72, 1093–1099. doi:10.1139/z94-147 Heffner, H.E., 1998. Auditory awareness. Appl. Anim. Behav. Sci. 57, 259–268. doi:10.1016/S0168-1591(98)00101-4 Kwan, J.Y., Bain, M.J., 2013. Owner attachment and problem behaviors related to relinquishment and training techniques of dogs. J. Appl. Anim. Welf. Sci. 16, 168–183. doi:10.1080/10888705.2013.768923 Lisberg, A.E., Snowdon, C.T., 2011. Effects of sex, social status and gonadectomy on countermarking by domestic dogs, Canis familiaris. Anim. Behav. 81, 757–764. Miller, P.E., Murphy, C.J., 1995. Vision in dogs. J. Am. Vet. Med. Assoc. 207, 1623– 1634. Millot, J.L., 1994. Olfactory and visual cues in the interaction systems between dogs and children. Behav. Processes 33, 177–188. doi:10.1016/0376-6357(94)900655 Neidhart, L., Boyd, R., 2002. Companion animal adoption study. J. Appl. Anim. Welf. Sci. 5, 175–192. doi:10.1207/S15327604JAWS0503_02 Olson, K.R., Levy, J.K., Norby, B., Crandall, M.M., Broadhurst, J.E., Jacks, S., Barton, R.C., Zimmerman, M.S., 2015. Inconsistent identification of pit bull-type dogs by shelter staff. Vet. J. 206, 197–202. Reid, P., Collins, K., 2012. Assessing conspecific aggression in fighting dogs, in: Proceedings of the Second Canine Science Forum. Vienna, Austria, p. 133. Salman, M.D., John G. New, J., Scarlett, J.M., Kass, P.H., Ruch-Gallie, R., Hetts, S., 1998. Human and animal factors related to relinquishment of dogs and cats in 12 selected animal shelters in the United States. J. Appl. Anim. Welf. Sci. 1, 207– 226. doi:10.1207/s15327604jaws0103_2 Serpell, J.A., Duffy, D.L., 2014. Dog breeds and their behavior, in: Domestic Dog Cognition and Behavior. Springer, pp. 31–57. Shabelansky, A., Dowling-Guyer, S., Quist, H., D’Arpino, S.S., McCobb, E., 2015. Consistency of shelter dogs’ behavior toward a fake versus real stimulus dog during a behavior evaluation. Appl. Anim. Behav. Sci. 163, 158–166. doi:10.1016/j.applanim.2014.12.001 Sternberg, S. 2002. Great Dog Adoptions: A Guide for Shelters. The Latham Foundation, Alameda, CA, pp. 9–28 Voith, V.L., Ingram, E., Mitsouras, K., Irizarry, K., 2009. Comparison of Adoption Agency Breed Identification and DNA Breed Identification of Dogs. J. Appl. Anim. Welf. Sci. 12, 253–262. doi:10.1080/10888700902956151
Walker, D.B., Walker, J.C., Cavnar, P.J., Taylor, J.L., Pickel, D.H., Hall, S.B., Suarez, J.C., 2006. Naturalistic quantification of canine olfactory sensitivity. Appl. Anim. Behav. Sci. 97, 241–254. Weiss, E., 2007. Meet Your Match SAFER™ manual and training guide. ASPCA.
Figure Legends Figure 1. Diagram illustrating how the Animal Behavior Lab was arranged.
Figure 2. Boxplot depicting the amount of time dogs spent orienting to the cat (dark gray bars) and control (light gray bars) stimuli during the visual and sound trials. The dark line in each box represents the median. The box encloses the middle half of the data, and the vertical lines represent the range of typical data values. Outliers are represented by circles. ** indicates p < 0.01.
Figure 3. Boxplot depicting the amount of time dogs spent sniffing the cat and control stimuli during the non-olfactory (dark gray bars) and olfactory (light gray bars) conditions. The dark line in each box represents the median. The box encloses the middle half of the data, and the vertical lines represent the range of typical data values. Outliers are represented by circles. * indicates p < 0.05.
Figure 4. Boxplot depicting the amount of time dogs that had (light gray bars) and had not (dark gray bars) killed or injured a cat or other small animal spent orienting to the stimuli. The dark line in each box represents the median. The box encloses the middle half of the data, and the vertical lines represent the range of typical data values. Outliers are represented by circles. # indicates p < 0.10; * indicates p < 0.05.
Table 1. Description of study participants. Name Lived with Age Cats at Time (years) of Study
Sex
Spayed/ Neutered/ Intact
Breed Reported by Owner
Breed Group
Order
Olfactory Condition
Abby Baylie Charlotte Crescent Daisy
Yes Yes Yes Yes Yes
4 3 6 3 2
Female Female Female Female Female
Intact Spayed Spayed Spayed Spayed
Non-Sporting Terrier Sporting Working Terrier
Cat First Control First Cat First Control First Control First
Olfactory Olfactory Non-Olfactory Non-Olfactory Non-Olfactory
Delaney Eve Ginger
Yes No Yes
2.5 4.5 6
Female Spayed Female Spayed Female Spayed
Terrier Toy Sporting
Cat First Control First Control First
Olfactory Non-Olfactory Non-Olfactory
Koda Lola Lola Lucy Mirka Mona Morgan Nyla Ruby Sophia Tessa Tori Zephyr
Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes No
2 2 3 3.5 4 1 2.5 7.5 7 7 4 4 6.5
Female Female Female Female Female Female Female Female Female Female Female Female Female
Dalmatian Fox Terrier Mix Cocker Spaniel Great Pyrenees Staffordshire Bull Terrier Pit Bull/Bull Terrier Pug/Pomeranian American Cocker Spaniel Siberian Husky Golden Retriever Pekingese Beagle Pit Bull Pug/Beagle Labrador Retriever Pit Bull Labrador Retriever Pug Siberian Husky English Bulldog Siberian Husky
Working Sporting Toy Hound Terrier Toy/Hound Sporting Terrier Sporting Toy Working Non-Sporting Working
Cat First Control First Control First Control First Cat First Control First Cat First Cat First Control First Cat First Control First Control First Cat First
Olfactory Olfactory Olfactory Non-Olfactory Olfactory Non-Olfactory Non-Olfactory Olfactory Non-Olfactory Olfactory Non-Olfactory Olfactory Non-Olfactory
Spayed Spayed Spayed Spayed Spayed Spayed Spayed Spayed Spayed Spayed Spayed Spayed Spayed
Andre Augie
Yes Yes
1 3
Male Male
Neutered Neutered
Ben Ben Bentley
Yes Yes No
2.5 8.5 2.5
Male Male Male
Neutered Neutered Neutered
Biso Boagrius
Yes Yes
2.5 1.5
Male Male
Neutered Neutered
Boris
Yes
3
Male
Neutered
Bruzer Buddy
Yes No
6 6
Male Male
Neutered Neutered
Charlie
Yes
2.5
Male
Neutered
Chopper Cooper Cooper
Yes Yes Yes
1 8 8
Male Male Male
Neutered Neutered Neutered
Dexter Dezel
Yes No
7 7
Male Male
Neutered Intact
Dooley Dougie
Yes No
2 3
Male Male
Neutered Neutered
Pit Bull Staffordshire Bull Terrier/Pharoah Hound St. Bernard Miniature Poodle Bernese Mountain Dog Mixed Breed Chesapeake Bay Retriever Dutch Shepherd/Pit Bull Pug/Beagle American Cocker Spaniel Golden Retriever/Hound Pit Bull Golden Retriever American Staffordshire Terrier Greyhound Miniture American Eskimo Golden Retriever Fox Terrier/ Hound/Border Collie
Terrier Terrier/Hound
Cat First Control First
Olfactory Olfactory
Working Non-Sporting Working
Cat First Control First Cat First
Non-Olfactory Olfactory Non-Olfactory
Terrier Sporting
Cat First Cat First
Non-Olfactory Non-Olfactory
Herding/Terrier
Control First
Olfactory
Toy/Hound Sporting
Control First Cat First
Olfactory Non-Olfactory
Sporting/Hound
Control First
Non-Olfactory
Terrier Sporting Terrier
Cat First Control First Control First
Olfactory Non-Olfactory Non-Olfactory
Hound Non-Sporting
Control First Control First
Olfactory Non-Olfactory
Sporting Terrier/Hound/ Herding
Control First Control First
Non-Olfactory Non-Olfactory
Duke
Yes
6
Male
Neutered
Duke Eddie
Yes Yes
6 8
Male Male
Neutered Intact
Ellsworth
Yes
2.5
Male
Neutered
Frankie
Yes
6
Male
Neutered
Gusippee Hadley Hogarth Huckleberr y
Yes Yes Yes Yes
2 2 4 2.5
Male Male Male Male
Neutered Neutered Neutered Neutered
Kodiak
Yes
1
Male
Intact
Lloyd
No
2
Male
Neutered
Louie Lukeaa Merle Milo Milo
No Yes Yes Yes No
3.5 5 5.5 4.5 6
Male Male Male Male Male
Neutered Neutered Neutered Neutered Neutered
Labrador Retriever Mix Greyhound Flat Coated Retriever Cavalier King Charles Spaniel Shih Tzu/Bichon Frise Maltese/Terrier Labrador Retriever Great Pyrenees Golden Retriever/ Sharpei/Chow Chow Shiloh Shepherd/ Carolina Dog Labrador Retriever/ Sharpei/Pit Bull Beagle German Shepherd Pit Bull Mix Beagle Mix Labrador Retriever/ Border Collie
Sporting
Control First
Non-Olfactory
Hound Sporting
Cat First Cat First
Olfactory Olfactory
Toy
Cat First
Olfactory
Non-Sporting
Cat First
Non-Olfactory
Terrier/Toy Sporting Working Sporting/NonSporting
Cat First Control First Cat First Control First
Non-Olfactory Non-Olfactory Non-Olfactory Olfactory
Herding/NonSporting Sporting/NonSporting/Terrier
Cat First
Non-Olfactory
Cat First
Non-Olfactory
Hound Herding Terrier Hound Sporting/Herding
Control First Cat First Control First Control First Cat First
Olfactory Olfactory Non-Olfactory Non-Olfactory Olfactory
Murphy
No
6
Male
Neutered
Labrador Retriever/ Rottweiler/Chow Chow
Sporting/Working/ Cat First Non-Sporting
Olfactory
Oliver
Yes
6
Male
Neutered
Herding
Control First
Olfactory
Puppy
Yes
7
Male
Neutered
Herding
Cat First
Non-Olfactory
Rooney Samson
Yes Yes
2 6.5
Male Male
Neutered Neutered
Non-Olfactory Olfactory
Yes
2
Male
Neutered
Terrier Sporting/NonSporting Toy/Terrier
Cat First Cat First
Studley
Pembroke Welsh Corgi Border Collie/ Shepherd Pit Bull Mix Golden Retriever/ Poodle Chihuahua/ American Staffordshire Terrier
Cat First
Non-Olfactory
Teppo
No
6
Male
Neutered
Terrier
Control First
Olfactory
Tucker Tucker Tyke Tyson
No No Yes No
4 5 5 7
Male Male Male Male
Neutered Neutered Neutered Neutered
Hound Hound Toy/Terrier Working
Cat First Control First Control First Cat First
Olfactory Olfactory Olfactory Non-Olfactory
Willie Winston Zeke
Yes Yes Yes
2 7 3
Male Male Male
Neutered Neutered Neutered
Jack Russell Terrier Mixed Breed Beagle Maltese/Yorkie St. Bernard/Great Pyrenees Maltese Beagle Mix Labrador Retriever
Toy Hound Sporting
Control First Cat First Cat First
Olfactory Olfactory Non-Olfactory
S0168-1591(17)30005-9 http://dx.doi.org/doi:10.1016/j.applanim.2016.12.016 APPLAN 4387
To appear in:
APPLAN
Received date: Revised date: Accepted date:
7-4-2016 20-12-2016 31-12-2016
Please cite this article as: Hoffman, Christy L., Workman, Miranda K., Roberts, Natalie, Handley, Stephanie, Dogs’ rto visual, auditory, and olfactory cat-related cues.Applied Animal Behaviour Science http://dx.doi.org/10.1016/j.applanim.2016.12.016 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Dogs’ responses to visual, auditory, and olfactory cat-related cues
Christy L. Hoffman, Miranda K. Workman, Natalie Roberts, & Stephanie Handley
Department of Animal Behavior, Ecology, and Conservation Canisius College 2001 Main Street, Buffalo, NY 14208
Correspondence should be addressed to Christy L. Hoffman, Department of Animal Behavior, Ecology, and Conservation, Canisius College, 2001 Main St., Buffalo, NY 14208 Email: [email protected] Phone: (716) 888-2775
Highlights
We tested dogs’ responses to visual and auditory cat-related and control stimuli.
Dogs oriented more to the auditory cat stimulus than to the visual cat stimulus.
Dogs that had hurt small animals were more attentive to the auditory stimuli.
Responses to cat sounds might predict which shelter dogs will get along with cats.
Abstract Standardized assessments have been developed to assess dogs’ behaviors around other dogs, but there currently is no validated way to predict how a dog in an animal shelter will behave around cats, unless the dog’s previous history is known. This study explored dogs’ responses to visual, auditory, and olfactory cat-related and control stimuli, and tested whether dogs known to interact safely with cats and other small animals responded differently to the stimuli than dogs known to have injured or killed such animals. We video recorded 69 dogs’ responses to the stimuli, and raters who were blind to the dogs’ behavioral histories coded the dogs’ reactions. Dogs differed in the amount of time they spent orienting to the cat and control visual stimuli and sounds. They spent significantly more time orienting to the cat sound than to the visual cat stimulus, to the visual cat stimulus than to the visual control stimulus, and to the control sound than to the visual control stimulus (for all, p < 0.01). Dogs that were presented with the visual stimuli in conjunction with the cat odor (i.e., cat urine) sniffed the visual control stimulus more than cats in the non-olfactory condition (p = 0.04), but they did not sniff the visual cat stimulus more. Dogs that had killed or injured a cat or other small animal spent more time orienting to the cat sound than dogs that did not have this history (p = 0.01). The results indicate that dogs are more responsive to auditory than visual or olfactory cat-related stimuli, and that it may be possible to use cat sounds to predict which shelter dogs are likely to fare well in homes with cats or other small animals.
Keywords: dog; cat; perception; behavioral assessment; predatory behavior
1. Introduction According to the Association for the Prevention of Cruelty to Animals (ASPCA, 2015), 3.9 million dogs enter animal shelters in the United States, and 1.2 million are euthanized annually. Dog owners relinquish their dogs to shelters for a variety of reasons, but behavior problems are frequently cited as a motivating factor (Diesel et al., 2010; Kwan and Bain, 2013; Salman et al., 1998). A dog brought into a new home is expected to adapt to the owner’s lifestyle and household, which may include children, dogs, and cats in addition to multiple adult humans. Dogs that do not behave appropriately with household members are at risk of being relinquished to shelters (Neidhart and Boyd, 2002). When a dog does end up in a shelter, the shelter may use a behavioral assessment to determine whether, and under what conditions, the dog should be rehomed. Commonly used behavioral assessments include Assess-a-Pet (Sternberg, 2002), a modified version of Assess-a-Pet (Bollen & Horowitz, 2008), and Safety Assessment for Evaluating Rehoming™ (SAFER) (Weiss, 2007). Some behavioral assessments use stuffed or plastic dog models and toddler-sized dolls to predict how shelter dogs will behave around dogs and children (Barnard et al., 2011; De Meester et al., 2011; Dowling-Guyer et al., 2011; Reid and Collins, 2012). However, there is no validated assessment to predict how a dog will behave around household cats and other small animals even though dogs vary greatly in their tendencies to direct predatory behaviors toward such animals. The full canine predatory motor pattern is orient > eye > stalk > chase > grab-bite > kill-bite > dissect > consume, and the movement of prey triggers it consistently in
wolves (Coppinger and Schneider, 1995). Due to the dog’s role as a scavenger, the predatory motor pattern is more relaxed and variable in dogs than in wolves (Coppinger and Coppinger, 2001). Indeed, in successful livestock guarding dogs, the predatory motor pattern is either nonexistent or weak (Coppinger and Schneider, 1995; Coppinger and Coppinger, 2001). A dog’s breed may provide some insights into the likelihood of engagement in predatory behaviors. For instance, German short-haired pointers, miniature schnauzers, and Siberian huskies have historically played important roles as hunters or controllers of vermin, and they outscore other breeds on a measure of predatory chasing behavior (Serpell and Duffy, 2014). Environmental factors, however, particularly during early development, impact how strictly a purebred dog will follow breed-typical motor patterns (Coppinger and Schneider, 1995). Due to a lack of information regarding many shelter dogs’ previous experiences and the fact that most dogs that enter a shelter are mixed breeds (Salman et al., 1998), a shelter may be reluctant to adopt a dog to a home that includes cats or other small animals unless the former owner is able to provide a detailed history. Other shelters may resort to using live cats to conduct informal assessments of dogs’ behaviors around cats, but such assessments have not been validated and may be stressful and potentially harmful for the cats employed. Given that previous studies have shown that dog models and dolls do provide some indication of how dogs respond to living dogs and children (Barnard et al., 2012; Shabelansky et al., 2015), it is possible that a dog’s response to a cat model may predict how a dog will respond to cats or other small animals.
Previous research examining dogs’ responses to dogs and children have relied upon visual representations of dogs and small children even though the dog’s umwelt differs substantially from our own. Dogs’ eyes are incredibly sensitive to movement, but dogs do not see as well as humans during the day (Miller and Murphy, 1995). Compared to humans, however, their senses of hearing and smell are much more sophisticated. They can detect sounds up to 44,000 Hz whereas humans can detect sounds up to 17,600 Hz (Heffner, 1998), and dogs’ noses are 10,000 to 100,000 times more sensitive to odors (Walker et al., 2006). Because dogs’ auditory and olfactory abilities are so refined, assessments of dogs’ responses to children and animals might be improved by including olfactory and auditory components in addition to visual components. In this experiment, we tested dogs’ responses to visual, olfactory, and auditory cat-related stimuli. We hypothesized that dogs that had previously harmed or killed cats or other small animals would be more attentive to these stimuli than dogs that had not. In addition, we hypothesized dogs would be more attentive to the auditory cat stimulus than the visual cat stimulus and that dogs would engage more with the visual stimuli when they were paired with cat odors.
2. Methods 2.1 Participants We used survey-based data collected from dog owners in Western New York (United States) to select dogs for this study, which took place in the Animal Behavior Lab on the Canisius College campus in Buffalo, NY, USA. The online survey focused on
dogs’ behaviors around cats and other small animals. We sought a variety of dog participants, ranging from those that had killed or injured cats or other small animals to those that had never exhibited any harmful or predatory behavior toward cats or other small animals. Dogs selected to participate in the experiment were required to meet the following eligibility requirements: were current on their rabies vaccine; were older than 6 months old but younger than 9 years old; had experienced no surgery or orthopedic problems within the previous 12 weeks; and had resided with the current family for at least 6 months. Dogs with a history of aggression toward humans were excluded from participating. Only one dog per household was eligible to participate to ensure the dog participants were statistically independent of one another. A total of 69 dogs met the selection criteria. Forty-eight were male, and 21 were female. Three males and one female were intact. Fifty-four lived with cats at the time of the study. Dog participants were between 1 year and 8.5 years of age (M = 4.28, SD = 2.13). Ten percent of participants (n = 7) had lived in the household for 6 months to 1 year; 54% (n = 37) had for between 1 year and 4 years; and 36% (n = 25) had for more than 4 years. Fifty-eight percent (n = 40) had been acquired from an animal shelter or rescue or had been found as a stray, and 22% (n =15) had been acquired from a breeder. The remaining dogs came from a friend or family member (n = 7), a newspaper or online ad (n = 6), or a pet shop (n = 1). When asked about their dog’s breed, 41 participants only listed one breed, and 28 listed multiple breeds. Based on the first breed participants listed, the following is a breakdown of the number of dogs in the sample that belonged to each breed group: herding: 5, hound: 8, non-sporting: 5, sporting: 19, terrier: 15, toy: 9, and working: 8. For
more details regarding each dog participant, including owner-reported breed information, please refer to Table 1.
***Table 1 about here***
2.2 Stimuli Visual Cat Stimulus. The cat stimulus was an animatronic children's toy (Hasbro FurReal Friends Lulu Interactive Animated White Persian Kitty Cat, Hasbro, Pawtucket, RI, USA). When switched on, the cat blinked, swished its tail, moved its paws forward, rotated its head, moved its ears, meowed, and purred. Visual Control Stimulus. The control stimulus was a white, zippered pillowcase that contained a motorized ball (Bumble Ball, Otis and Claude, Union City, CA, USA) and plastic packing material. The pillowcase had two fabric eyes affixed to the end opposite the zipper. The pillowcase moved and vibrated when the Bumble Ball inside it was activated. Cat and Control Sounds. Auditory trials consisted of playing recordings of cat vocalizations and coins dropping. Each recording lasted 60 seconds. The recordings were edited from videos that were available on Youtube (www.youtube.com), and the sound files are included as supplementary files. The cat vocalization recording primarily included cats meowing but also included two cat growls. We chose to use the sounds of coins dropping as the control sound because they, like the cat sounds, occurred intermittently. In addition, there was variation in the sounds the coins made as they dropped, just as there was variation in the sounds the cats made. Each recording lasted
60 seconds and was no louder than 60 decibels. The cat and control sounds were transmitted through external speakers (Altec Lansing inMotion Speakers, Altec Lansing, New York City, NY, USA) attached to a laptop (Hewlett-Packard ProBook, HewlettPackard, Palo Alto, CA, USA). The laptop and speakers were in a room that adjoined the Animal Behavior Lab. The door between the two rooms remained open, although a baby gate kept dogs from entering this room. A custom-made 1.5m x 1.5m room divider blocked the laptop and speakers from the dog’s view. At the start of each trial, dogs were about 5 m away from the audio equipment. Cat Odor. In the olfactory condition, a polypropylene plastic tube that contained a piece of cotton soaked in cat urine was placed inside the cat and pillowcase. In the cat condition, the tube was taped to the cat’s battery compartment, which was located behind a layer of Velcro and fur on the underside of the cat. In the control condition, the tube was taped to the Bumble Ball that was zipped inside the pillowcase. The cap of the tube contained a hole so that the odor could escape. Each dog in the olfactory condition was exposed to odor from a single cat, although we used urine from eight different cats in the study. A local animal shelter provided the urine samples, which were expressed from cats prior to sterilization surgery. The samples were kept refrigerated until use, and we used the samples within one week of collection. The sexes and ages of the cats sampled are unknown. 2.3 Experimental Design Each dog experienced 6 novel stimuli, one at a time, in 6 separate trials and was randomly assigned to either an olfactory or non-olfactory condition. The first two trials included inanimate cat and control stimuli (visual); the second set of trials included
animate cat and control stimuli (visual); and the final set of trials included cat vocalizations and control sounds (auditory). We used random assignment to determine whether each dog experienced cat or control stimuli first within each set of trials. Thirtyfive dogs were presented with cat stimuli before control stimuli within each set of trials, and 34 were presented with control stimuli first. To prevent the laboratory from becoming contaminated with cat odors and interfering with the non-olfactory condition, all dogs assigned to the non-olfactory condition (n = 36) participated in the study before dogs assigned to the olfactory condition participated (n = 33). The dogs and owners selected for the study came to the Animal Behavior Lab for a visit lasting 30-45 minutes. Figure 1 illustrates how the lab was arranged for the study. Upon the arrival of the dog and owner, the experimenter attached a 6m long line to the dog’s collar or harness, and we removed the dog’s regular leash and any equipment that was aversive and/or impeded movement. The dog had 5 minutes to familiarize himself/herself with the experimenter and setting. The dog’s owner held the long line during the first 2 minutes of exploration, and a member of the study team (CH or MW) held the long line during the latter 3 minutes so that the dog’s owner could take a seat behind an exercise pen in the front, left corner of the lab and the dog could acclimate to the handler. We used two high definition video cameras (Panasonic HC-V720, Panasonic, Kadoma, Osaka Prefecture, Japan) to film the dog from 2 camera angles the entire time he/she was in the laboratory.
***Figure 1 about here***
Following the acclimation period, the handler walked the dog behind a custommade 1.5m x 1.5m room divider and shortened the lead to restrict the dog’s ability to move or see beyond the room divider. A research assistant then entered the lab and placed either the cat or pillowcase on a marked position 3m in front of the divider. The room divider prevented the dog from seeing the research assistant or prop during the set-up period that preceded each visual trial. After placing the study prop, the research assistant returned to the adjoining room so that she could remain out of the dog’s sight during the visual trials. Once out of sight, the research assistant announced the trial number, signaling the dog’s handler that the dog could move out from behind the room divider and approach the prop. Once the handler allowed the dog to move out from behind the room divider, the dog had 75 seconds to investigate the stimulus, upon which time the research assistant announced the end of the trial and the handler guided the dog back behind the room divider. Once the dog was behind the room divider and so could not see the research assistant or study props, the research assistant removed the first inanimate stimulus and replaced it with the other inanimate stimulus. As in the first trial, the dog’s response to the second inanimate stimulus was recorded for 75 seconds. The animate cat and control trials followed the inanimate trials and were performed in the same manner. The 75-second trial length was determined based on pilot testing of dogs’ responses to the visual cat and control stimuli. At the start of the sound trials, which immediately followed the animate trials, the dog sat or stood on a marked spot in front of the room divider and the dog’s handler shortened the lead to restrict the dog’s ability to move beyond that spot. The room divider that blocked the speakers and laptop from the dog’s view also blocked the
research assistant from the dog’s view. Once the auditory trial started, the dog was allowed to move and investigate the sound. The trial was 75 seconds long, beginning when the sound started and ending 15 seconds after the sound terminated. Following the presentation of the first sound, the handler guided the dog back to the starting point, and then the second sound was presented. Typically, the inter-trial interval between each of the 6 trials was between 30s and 60s. During each trial, the handler held the leash loosely, only restricting the dog’s movement when he/she attempted to enter areas marked as out of view of both camera angles. The handler and the owner did not interact or make eye contact with the dog during the trials. Some owners were given the option of reading a magazine during the trials, and others chose to engage with their cell phones during this time. Sample videos of the visual and auditory trials have been included as supplementary files. 2.4 Ethical Statement Canisius College’s Institutional Animal Care and Use Committee approved the study prior to the onset of data collection. Dogs’ owners signed a consent form allowing their dogs to participate in the study and provided proof that their dog had an up-to-date rabies vaccine. 2.5 Measurements Two research assistants used Noldus Observer XT 11.0 to code behaviors observed during the first 60 seconds of each trial. Behaviors recorded included orienting to stimulus, which was defined as looking toward and appearing to focus on the stimulus for at least one second while the head did not move, and sniffing the stimulus, which was defined as frequent, short inhalations through the nose directed at the
stimulus while the dog’s nose was within 2 cm of the stimulus. Both observers coded 10% of the videos to establish interrater reliability, which we calculated using Cohen’s Kappa coefficients. Kappa ranged from 0.84 to 1.00, and the average was 0.92. The research assistants coded the videos blind to dogs’ histories with cats and other small animals, and to whether each dog was in the olfactory or non-olfactory condition. 2.6 Data Analysis Dependent variables examined in the analyses included the following: time spent orienting to stimulus and time spent sniffing stimulus. According to the Shapiro-Wilk test, the data were not normally distributed, and so we ran non-parametric analyses. We used Friedman’s two-way analysis of variance and pairwise comparisons to compare the amounts of time the dogs oriented to the visual cat stimulus, visual control stimulus, cat sound, and control sound. Mann-Whitney U tests were performed to examine whether the order of presentation of the visual and auditory stimuli influenced the amount of time dogs oriented to the stimuli; whether dogs in the olfactory and nonolfactory conditions differed in the amount of time they oriented to or sniffed the animatronic cat and visual control stimuli; and whether living with a cat or a history of harming or killing cats or other small animals influenced the amount of time the dogs oriented to the visual and auditory stimuli. Wilcoxon signed rank tests were used to compare how much time dogs oriented to the inanimate and animate cat and control stimuli and how much time dogs in the olfactory condition sniffed the cat and control stimuli.
3. Results
There was no relationship between breed group and the amount of time dogs spent orienting to any of the stimuli (for all, p > 0.05). Due to this and because visual identification of mixed breeds is not reliable (Olson et al., 2015; Voith et al., 2009), all dogs were grouped together in the analyses that follow. 3.1 Visual and Auditory Conditions Dogs spent significantly more time orienting to the animate visual control stimulus than to the inanimate visual control stimulus (Z = 2.36, p = 0.02), but dogs did not differ in the amount of time they oriented to the inanimate and animate cat stimuli (Z = -0.18, p = 0.86). Because dogs did not differ in the amount of time they oriented to the inanimate and animate cat stimuli, the remaining analyses of dogs’ responses to the visual cat stimulus and visual control stimulus will focus on the inanimate condition. Dogs differed in the amount of time they spent orienting to the visual cat and control stimuli and cat and control sounds (χ2(3) = 108.58, p < 0.001) (Figure 2). Pairwise comparisons indicated that the dogs spent significantly more time orienting to the cat sound than the control sound, to the cat sound than to the visual cat stimulus, to the visual cat stimulus than to the visual control stimulus, and to the control sound than to the visual control stimulus (for all, p < 0.01).
***Figure 2 about here***
Whether the visual cat stimulus was presented before or after the visual control stimulus did not affect how long the dogs oriented to the visual cat stimulus (Z = 0.88, p = 0.38). Similarly, there was no effect of order on how long the dogs oriented to the cat
sound (Z = 0.64, p = 0.52). Dogs oriented longer to the visual control stimulus if it was presented before the visual cat stimulus (Z = -1.97, p = 0.049). They oriented longer to the control sound if it was presented after the cat sound (Z = 2.84, p = 0.005). 3.2 Olfactory Condition There was no effect of olfactory condition on the amount of time the dogs oriented to the visual cat stimulus or visual control stimulus (cat: Z = 0.69, p = 0.49; object: Z = 1.75, p = 0.08) (Figure 3). Dogs in both the non-olfactory and olfactory conditions spent significantly more time sniffing the cat stimulus than the control stimulus (non-olfactory: Z = -4.29, p < 0.001; olfactory: Z = -3.47, p = 0.001). Dogs in the non-olfactory and olfactory conditions did not differ in the amount of time they sniffed the visual cat stimulus (Z = 1.17, p = 0.24). However, dogs in the olfactory condition sniffed the visual control stimulus significantly longer than dogs in the nonolfactory condition (Z = 2.09, p = 0.04).
***Figure 3 about here***
3.3 History with Cats and Other Small Animals There was no relationship between dogs that did and did not live with a cat and the amount of time they spent orienting to the visual cat stimulus (Z = -0.89, p = 0.38), visual control stimulus (Z = -0.19, p = 0.85), or control sound (Z = -0.68, p = 0.50). There was a nonsignificant tendency for dogs that did not live with cats to spend more time than dogs that lived with cats orienting to the cat sound (Z = -1.73, p = 0.08).
Four of the 69 dogs had killed or injured a cat, and 3 of those had also killed or injured another type of small animal. An additional 14 dogs had killed or injured at least one small animal but not a cat. Dogs that had and had not killed or injured a cat or other small animal did not differ in the amount of time they oriented to the visual cat stimulus (Z = -0.57, p = 0.57) or the visual control stimulus (Z = -0.08, p = 0.93) (Figure 4). Within the olfactory condition, there was no relationship between whether a dog had killed or injured a cat or other small animal and the amount of time the dog spent sniffing the visual cat stimulus (Z = 0.62, p = 0.56) or the visual control stimulus (Z = 0.09, p = 0.95). Dogs that had killed or injured a cat or other small animal, however, did spend more time orienting to the cat sound than did dogs that had not (Z = 2.52, p = 0.01), and there was a nonsignificant tendency for those dogs to spend more time orienting to the control sound (Z = 1.79, p = 0.07) (Figure 4).
***Figure 4 about here***
4. Discussion Dogs were more attentive to the visual cat stimulus than the visual control stimulus and the cat sound than the control sound. In addition, they attended more to the auditory cat stimulus than the visual cat stimulus. The latter findings parallel results from previous work that has shown that dogs respond more to dog sounds than to visual representations of dogs (Déaux et al., 2015). Dogs in the non-olfactory and olfactory conditions did not differ in the amount of time they spent sniffing the cat stimulus, but dogs in the olfactory condition spent more
time than dogs in the non-olfactory condition sniffing the control stimulus. This finding may provide insights into how dogs perceived the cat and control stimuli. If dogs viewed the visual cat stimulus as being cat-like, the associated cat urine smell in the olfactory condition would have been congruent with the dogs’ expectations about the stimulus; thus, the dogs did not need to spend more time investigating the cat stimulus in the olfactory condition than in the non-olfactory condition. The dogs’ increased interest in the control condition, however, may have been due to the cat odor being unexpected in the presence of the control stimulus; that is, the dogs’ interest may have been piqued by something that did not look like a cat but smelled like a cat. Previous work has shown that dogs look longer at stimuli when experiencing incongruent information from two sensory modalities. For instance, Adachi, Kuwahata, and Fujita (2007) reported that dogs looked longer at visual images of their owner if an audio recording of a stranger’s voice, rather than their owner’s voice, preceded the image. Although dogs that had and had not killed or injured a cat or other small animal did not differ in their responses to the visual stimuli, dogs that had such a history spent significantly more time orienting toward the cat sound than dogs without this history. In addition, there was a nonsignificant tendency for these dogs to spend more time orienting to the control sound. These findings indicate that dogs that have killed or injured cats or other small animals may be hypersensitive to auditory information, particularly if it sounds like cat vocalizations. Unfortunately, our sample included only four dogs that had killed or injured cats, and so we were unable to examine killing and injuring cats independently of killing and injuring other small animals.
We expected dogs would be more attentive to the animate visual cat stimulus than the inanimate visual cat stimulus because dogs are highly sensitive to movement (Miller and Murphy, 1995), yet dogs did not show more interest in the animate cat. There are a few possible explanations for this. First, due to study design constraints, the animate cat was always presented after dogs had been exposed to the inanimate cat. As a result, the novelty of the cat’s visual appearance may have dissipated prior to the animate cat trial. Furthermore, although parts of the cat moved during the animate condition, the cat did not walk or run. Had the stimulus exhibited more pronounced movements, we may have seen differences in dogs’ responses to the animate and inanimate cat stimuli. Although dogs showed more interest in the auditory trials than the visual ones, it is possible that the cat sounds did not sound quite like live cat vocalizations to the dogs studied. Dogs can hear frequencies that humans cannot (Heffner, 1998), and so recordings created for human ears may include high frequencies detectable to dogs but not to humans. Three pieces of evidence, however, suggest the dogs may have perceived the sounds as originating from cats. First, the dogs spent significantly more time orienting to the cat sound than the control sound. In addition, dogs spent more time orienting to the control sound when it followed the cat sound than when it preceded it, suggesting the cat sound may have heightened the dogs’ attentiveness to sounds. Finally, at the conclusion of their study visit, dogs were walked on leash through the room from which the experimental sounds were played, and as they passed through, numerous dogs engaged in intense sniffing behaviors and pulled on leash toward the
side of the room from which the sounds originated. One interpretation of this behavior is that the dogs were searching for and expecting to find cats. Cat urine affected dogs’ behavior in the visual control condition, but it is certainly worth questioning whether cat urine is the most ideal cat-related odor to present to dogs. Given dogs’ documented tendencies to sniff ano-genital regions when greeting other dogs and other species (Millot, 1994), dogs’ high level of interest in other dogs’ urine (Lisberg and Snowdon, 2011), and cats’ tendencies to employ urine marking as a way to communicate with other cats (Bradshaw and Cameron-Beaumont, 2000), it is certainly plausible that dogs learn important information about cats from odors contained in their urine. Dogs may have responded differently, however, had the visual stimuli included scent marks derived from glandular secretions from cats’ faces and tail areas in lieu of urine. Such secretions are thought to play an important role in cats’ intraspecific interactions (Feldman, 1994). Findings from this study suggest it may be possible to develop an assessment tool that uses cat sounds to predict whether a dog residing in an animal shelter will be successful if adopted into a household that includes a cat or other small animals. Such an assessment, however, may indicate some dogs should not be rehomed with cats even though they may, in reality, be fine with cats. Thus, it is important that any such behavioral assessment be used in conjunction with other sources of information about the dog's behavior, such as information provided by the owner at the time of surrender and by kennel staff and volunteers who routinely interact with the dog. The detailed reports that dog participants’ owners provided indicated that half of the dogs that had killed or injured a cat or other small animal resided with at least one cat at the time of
the study, and most of these dogs coexisted peacefully with household cats. As only four dogs in our sample had actually killed or injured a cat, more data are needed to determine if such dogs consistently orient more toward cat sounds than dogs without such a history. Furthermore, additional testing is needed to determine whether an assessment could specifically predict dogs’ responses to indoor cats because, as our survey data indicate (Hoffman and Workman, unpublished data), some dogs interact appropriately with cats when indoors but chase cats when outdoors. 5. Conclusion We tested dogs’ responses to visual, auditory, and olfactory cat-related stimuli and found that dogs were most attentive to the auditory stimulus. Dogs showed no more interest in the olfactory cat condition than in the non-olfactory cat condition, suggesting that dogs perceived the visual cat stimulus to be cat-like, regardless of odor condition. Furthermore, dogs that had injured or killed cats or other small animals were more attentive to the auditory cat stimulus than those that had not. Our findings indicate that it may be possible to use recordings of cat vocalizations to assess which shelter dogs are likely to fare well in a home with cats or other small animals.
Acknowledgements We are grateful to the owners of the participating dogs for completing the study survey and bringing their dogs to campus. We thank Colleen Bates and Raechel Crosby for their assistance with this project and two reviewers for helpful comments on the manuscript. This study was supported by a grant to CH and MW from the Association of Professional Dog Trainers Foundation, a grant to CH from the Al and Noura Gress Foundation, and by funding to SH and NR from the Canisius Earning Excellence Program.
Bibliography Adachi, I., Kuwahata, H., Fujita, K., 2007. Dogs recall their owner’s face upon hearing the owner’s voice. Anim. Cogn. 10, 17–21. ASPCA, 2015. Pet statistics [WWW Document]. ASPCA. URL https://www.aspca.org/animal-homelessness/shelter-intake-and-surrender/petstatistics (accessed 11.25.15). Barnard, S., Passalacqua, C., Capra, A., Marshall-Pescini, S., Previde, E.P., Valsecchi, P., 2011. Social behavioral profile of different dog breeds. J. Vet. Behav. Clin. Appl. Res. 6, 83–84. Barnard, S., Siracusa, C., Reisner, I., Valsecchi, P., Serpell, J.A., 2012. Validity of model devices used to assess canine temperament in behavioral tests. Appl. Anim. Behav. Sci. 138, 79–87. doi:10.1016/j.applanim.2012.02.017 Bollen, K.S., Horowitz, J., 2008. Behavioral evaluation and demographic information in the assessment of aggressiveness in shelter dogs. Appl. Anim. Behav. Sci. 112, 120–135. Bradshaw, J., Cameron-Beaumont, C., 2000. The signalling repertoire of the domestic cat and its undomesticated relatives. Domest. Cat Biol. Its Behav. 67–94. Coppinger, R., Coppinger, L., 2001. Dogs: A Startling New Understanding of Canine Origin, Behavior & Evolution. New York: Scribner. Coppinger, R., Schneider, R., 1995. Evolution of working dogs. Domest. Dog Its Evol. Behav. Interact. People 21–47. Déaux, É.C., Clarke, J.A., Charrier, I., 2015. Aggressive bimodal communication in domestic dogs, Canis familiaris. PloS One 10, e0142975.
De Meester, R.H., Pluijmakers, J., Vermeire, S., Laevens, H., 2011. The use of the socially acceptable behavior test in the study of temperament of dogs. J. Vet. Behav. Clin. Appl. Res. 6, 211–224. doi:10.1016/j.jveb.2011.01.003 Diesel, G., Brodbelt, D., Pfeiffer, D.U., 2010. Characteristics of relinquished dogs and their owners at 14 rehoming centers in the United Kingdom. J. Appl. Anim. Welf. Sci. 13, 15–30. doi:10.1080/10888700903369255 Dowling-Guyer, S., Marder, A., D’Arpino, S., 2011. Behavioral traits detected in shelter dogs by a behavior evaluation. Appl. Anim. Behav. Sci. 130, 107–114. doi:10.1016/j.applanim.2010.12.004 Feldman, H.N., 1994. Methods of scent marking in the domestic cat. Can. J. Zool. 72, 1093–1099. doi:10.1139/z94-147 Heffner, H.E., 1998. Auditory awareness. Appl. Anim. Behav. Sci. 57, 259–268. doi:10.1016/S0168-1591(98)00101-4 Kwan, J.Y., Bain, M.J., 2013. Owner attachment and problem behaviors related to relinquishment and training techniques of dogs. J. Appl. Anim. Welf. Sci. 16, 168–183. doi:10.1080/10888705.2013.768923 Lisberg, A.E., Snowdon, C.T., 2011. Effects of sex, social status and gonadectomy on countermarking by domestic dogs, Canis familiaris. Anim. Behav. 81, 757–764. Miller, P.E., Murphy, C.J., 1995. Vision in dogs. J. Am. Vet. Med. Assoc. 207, 1623– 1634. Millot, J.L., 1994. Olfactory and visual cues in the interaction systems between dogs and children. Behav. Processes 33, 177–188. doi:10.1016/0376-6357(94)900655 Neidhart, L., Boyd, R., 2002. Companion animal adoption study. J. Appl. Anim. Welf. Sci. 5, 175–192. doi:10.1207/S15327604JAWS0503_02 Olson, K.R., Levy, J.K., Norby, B., Crandall, M.M., Broadhurst, J.E., Jacks, S., Barton, R.C., Zimmerman, M.S., 2015. Inconsistent identification of pit bull-type dogs by shelter staff. Vet. J. 206, 197–202. Reid, P., Collins, K., 2012. Assessing conspecific aggression in fighting dogs, in: Proceedings of the Second Canine Science Forum. Vienna, Austria, p. 133. Salman, M.D., John G. New, J., Scarlett, J.M., Kass, P.H., Ruch-Gallie, R., Hetts, S., 1998. Human and animal factors related to relinquishment of dogs and cats in 12 selected animal shelters in the United States. J. Appl. Anim. Welf. Sci. 1, 207– 226. doi:10.1207/s15327604jaws0103_2 Serpell, J.A., Duffy, D.L., 2014. Dog breeds and their behavior, in: Domestic Dog Cognition and Behavior. Springer, pp. 31–57. Shabelansky, A., Dowling-Guyer, S., Quist, H., D’Arpino, S.S., McCobb, E., 2015. Consistency of shelter dogs’ behavior toward a fake versus real stimulus dog during a behavior evaluation. Appl. Anim. Behav. Sci. 163, 158–166. doi:10.1016/j.applanim.2014.12.001 Sternberg, S. 2002. Great Dog Adoptions: A Guide for Shelters. The Latham Foundation, Alameda, CA, pp. 9–28 Voith, V.L., Ingram, E., Mitsouras, K., Irizarry, K., 2009. Comparison of Adoption Agency Breed Identification and DNA Breed Identification of Dogs. J. Appl. Anim. Welf. Sci. 12, 253–262. doi:10.1080/10888700902956151
Walker, D.B., Walker, J.C., Cavnar, P.J., Taylor, J.L., Pickel, D.H., Hall, S.B., Suarez, J.C., 2006. Naturalistic quantification of canine olfactory sensitivity. Appl. Anim. Behav. Sci. 97, 241–254. Weiss, E., 2007. Meet Your Match SAFER™ manual and training guide. ASPCA.
Figure Legends Figure 1. Diagram illustrating how the Animal Behavior Lab was arranged.
Figure 2. Boxplot depicting the amount of time dogs spent orienting to the cat (dark gray bars) and control (light gray bars) stimuli during the visual and sound trials. The dark line in each box represents the median. The box encloses the middle half of the data, and the vertical lines represent the range of typical data values. Outliers are represented by circles. ** indicates p < 0.01.
Figure 3. Boxplot depicting the amount of time dogs spent sniffing the cat and control stimuli during the non-olfactory (dark gray bars) and olfactory (light gray bars) conditions. The dark line in each box represents the median. The box encloses the middle half of the data, and the vertical lines represent the range of typical data values. Outliers are represented by circles. * indicates p < 0.05.
Figure 4. Boxplot depicting the amount of time dogs that had (light gray bars) and had not (dark gray bars) killed or injured a cat or other small animal spent orienting to the stimuli. The dark line in each box represents the median. The box encloses the middle half of the data, and the vertical lines represent the range of typical data values. Outliers are represented by circles. # indicates p < 0.10; * indicates p < 0.05.
Table 1. Description of study participants. Name Lived with Age Cats at Time (years) of Study
Sex
Spayed/ Neutered/ Intact
Breed Reported by Owner
Breed Group
Order
Olfactory Condition
Abby Baylie Charlotte Crescent Daisy
Yes Yes Yes Yes Yes
4 3 6 3 2
Female Female Female Female Female
Intact Spayed Spayed Spayed Spayed
Non-Sporting Terrier Sporting Working Terrier
Cat First Control First Cat First Control First Control First
Olfactory Olfactory Non-Olfactory Non-Olfactory Non-Olfactory
Delaney Eve Ginger
Yes No Yes
2.5 4.5 6
Female Spayed Female Spayed Female Spayed
Terrier Toy Sporting
Cat First Control First Control First
Olfactory Non-Olfactory Non-Olfactory
Koda Lola Lola Lucy Mirka Mona Morgan Nyla Ruby Sophia Tessa Tori Zephyr
Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes No
2 2 3 3.5 4 1 2.5 7.5 7 7 4 4 6.5
Female Female Female Female Female Female Female Female Female Female Female Female Female
Dalmatian Fox Terrier Mix Cocker Spaniel Great Pyrenees Staffordshire Bull Terrier Pit Bull/Bull Terrier Pug/Pomeranian American Cocker Spaniel Siberian Husky Golden Retriever Pekingese Beagle Pit Bull Pug/Beagle Labrador Retriever Pit Bull Labrador Retriever Pug Siberian Husky English Bulldog Siberian Husky
Working Sporting Toy Hound Terrier Toy/Hound Sporting Terrier Sporting Toy Working Non-Sporting Working
Cat First Control First Control First Control First Cat First Control First Cat First Cat First Control First Cat First Control First Control First Cat First
Olfactory Olfactory Olfactory Non-Olfactory Olfactory Non-Olfactory Non-Olfactory Olfactory Non-Olfactory Olfactory Non-Olfactory Olfactory Non-Olfactory
Spayed Spayed Spayed Spayed Spayed Spayed Spayed Spayed Spayed Spayed Spayed Spayed Spayed
Andre Augie
Yes Yes
1 3
Male Male
Neutered Neutered
Ben Ben Bentley
Yes Yes No
2.5 8.5 2.5
Male Male Male
Neutered Neutered Neutered
Biso Boagrius
Yes Yes
2.5 1.5
Male Male
Neutered Neutered
Boris
Yes
3
Male
Neutered
Bruzer Buddy
Yes No
6 6
Male Male
Neutered Neutered
Charlie
Yes
2.5
Male
Neutered
Chopper Cooper Cooper
Yes Yes Yes
1 8 8
Male Male Male
Neutered Neutered Neutered
Dexter Dezel
Yes No
7 7
Male Male
Neutered Intact
Dooley Dougie
Yes No
2 3
Male Male
Neutered Neutered
Pit Bull Staffordshire Bull Terrier/Pharoah Hound St. Bernard Miniature Poodle Bernese Mountain Dog Mixed Breed Chesapeake Bay Retriever Dutch Shepherd/Pit Bull Pug/Beagle American Cocker Spaniel Golden Retriever/Hound Pit Bull Golden Retriever American Staffordshire Terrier Greyhound Miniture American Eskimo Golden Retriever Fox Terrier/ Hound/Border Collie
Terrier Terrier/Hound
Cat First Control First
Olfactory Olfactory
Working Non-Sporting Working
Cat First Control First Cat First
Non-Olfactory Olfactory Non-Olfactory
Terrier Sporting
Cat First Cat First
Non-Olfactory Non-Olfactory
Herding/Terrier
Control First
Olfactory
Toy/Hound Sporting
Control First Cat First
Olfactory Non-Olfactory
Sporting/Hound
Control First
Non-Olfactory
Terrier Sporting Terrier
Cat First Control First Control First
Olfactory Non-Olfactory Non-Olfactory
Hound Non-Sporting
Control First Control First
Olfactory Non-Olfactory
Sporting Terrier/Hound/ Herding
Control First Control First
Non-Olfactory Non-Olfactory
Duke
Yes
6
Male
Neutered
Duke Eddie
Yes Yes
6 8
Male Male
Neutered Intact
Ellsworth
Yes
2.5
Male
Neutered
Frankie
Yes
6
Male
Neutered
Gusippee Hadley Hogarth Huckleberr y
Yes Yes Yes Yes
2 2 4 2.5
Male Male Male Male
Neutered Neutered Neutered Neutered
Kodiak
Yes
1
Male
Intact
Lloyd
No
2
Male
Neutered
Louie Lukeaa Merle Milo Milo
No Yes Yes Yes No
3.5 5 5.5 4.5 6
Male Male Male Male Male
Neutered Neutered Neutered Neutered Neutered
Labrador Retriever Mix Greyhound Flat Coated Retriever Cavalier King Charles Spaniel Shih Tzu/Bichon Frise Maltese/Terrier Labrador Retriever Great Pyrenees Golden Retriever/ Sharpei/Chow Chow Shiloh Shepherd/ Carolina Dog Labrador Retriever/ Sharpei/Pit Bull Beagle German Shepherd Pit Bull Mix Beagle Mix Labrador Retriever/ Border Collie
Sporting
Control First
Non-Olfactory
Hound Sporting
Cat First Cat First
Olfactory Olfactory
Toy
Cat First
Olfactory
Non-Sporting
Cat First
Non-Olfactory
Terrier/Toy Sporting Working Sporting/NonSporting
Cat First Control First Cat First Control First
Non-Olfactory Non-Olfactory Non-Olfactory Olfactory
Herding/NonSporting Sporting/NonSporting/Terrier
Cat First
Non-Olfactory
Cat First
Non-Olfactory
Hound Herding Terrier Hound Sporting/Herding
Control First Cat First Control First Control First Cat First
Olfactory Olfactory Non-Olfactory Non-Olfactory Olfactory
Murphy
No
6
Male
Neutered
Labrador Retriever/ Rottweiler/Chow Chow
Sporting/Working/ Cat First Non-Sporting
Olfactory
Oliver
Yes
6
Male
Neutered
Herding
Control First
Olfactory
Puppy
Yes
7
Male
Neutered
Herding
Cat First
Non-Olfactory
Rooney Samson
Yes Yes
2 6.5
Male Male
Neutered Neutered
Non-Olfactory Olfactory
Yes
2
Male
Neutered
Terrier Sporting/NonSporting Toy/Terrier
Cat First Cat First
Studley
Pembroke Welsh Corgi Border Collie/ Shepherd Pit Bull Mix Golden Retriever/ Poodle Chihuahua/ American Staffordshire Terrier
Cat First
Non-Olfactory
Teppo
No
6
Male
Neutered
Terrier
Control First
Olfactory
Tucker Tucker Tyke Tyson
No No Yes No
4 5 5 7
Male Male Male Male
Neutered Neutered Neutered Neutered
Hound Hound Toy/Terrier Working
Cat First Control First Control First Cat First
Olfactory Olfactory Olfactory Non-Olfactory
Willie Winston Zeke
Yes Yes Yes
2 7 3
Male Male Male
Neutered Neutered Neutered
Jack Russell Terrier Mixed Breed Beagle Maltese/Yorkie St. Bernard/Great Pyrenees Maltese Beagle Mix Labrador Retriever
Toy Hound Sporting
Control First Cat First Cat First
Olfactory Olfactory Non-Olfactory