- Email: [email protected]
Wolf-pack hunting strategy: an emergent collective behavior described by a classical robotic model
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Journal of Veterinary Behavior, Vol 6, No 1, January/February 2011
the way we treat and educate dogs and the way humans have to be respected. Second, dogs’ welfare is guaranteed along the activities, as dogs’ welfare is precisely the subject matter of the course, and dogs are always under the care and supervision of their owners (AEPA-Euskadi trainers) and are never left inside the prison. Third, to be present throughout the reintegration process (inside and outside the prison) reinforces the confidence, tranquillity and stability of the inmates. Key words: dog welfare; dog assisted activity; pro-social skills; prison inmates WOLF-PACK HUNTING STRATEGY: AN EMERGENT COLLECTIVE BEHAVIOR DESCRIBED BY A CLASSICAL ROBOTIC MODEL C. Muro1,*, R. Escobedo1,2, R.P. Coppinger3, L. Spector3,4 1 Assistance Dog Association AEPA-Euskadi, C/Pte. Deusto 7 - 48014 Bilbao, Vizcaya, Spain 2 Dept. of Applied Mathematics and Computational Sciences, University of Cantabria, 39005 Santander, Spain 3 School of Cognitive Science, Hampshire College, Amherst MA 01002, USA 4 Dept. of Computer Science, University of Massachusetts, Amherst MA 01003, USA *Corresponding author: [email protected] Wolf-pack social behaviors are considered highly organized social mechanisms in which a sophisticated communication system plays an essential role. Among these complex social interactions, wolf-pack hunting strategies are often presented as the proof that a social structure sustains the relation between pack members, and, still, that this social structure is based on hierarchical rules. After the advent of robotic science and artificial intelligence models of swarms, flocks and herds, complex behaviors are known to emerge from the combination of small sets of simple rules controlling the single behavior of each individual. In particular, multi-robot models have shown to be effective in describing capture processes often called hunts. A robot hunting model is presented in which two simple decentralized laws for the movement of each wolf-bot account for reproducing the main features of the wolfpack hunting ethogram: tracking the prey, carrying out the pursuit, encircling the prey and harassing it until the capture is considered over. Wolf-bots are all autonomous and indistinguishable from one another, therefore interchangeable–the geometrical position of the prey and of the other wolf-bots, especially those close to the prey, being the only information they need. Numerical simulations are carried out for multiple combinations of the parameters: pack size ranging from 2 to 20 members, different relative positions and speeds, etc. Prey movement is arbitrarily selected to be successively still, moving describing large circles, first with constant speed and after with positive or negative acceleration, and simulating an escaping movement.
The results show that hunting in packs is an emergent group behavior which does not necessarily rely on effective communication between the individuals participating in the hunt. With special emphasis, it is shown that no hierarchy is needed in the group to achieve the task properly. Key words: wolf-pack hunting ethogram; social emergent behavior; robotic model
HAPPY TAIL WAGGING: A LABORATORY ARTIFACT? LATERAL TAIL WAGGING IN THE FIELD Benigno Paz1, Ram on Escobedo2,3,* 1 Kns ediciones, 15780 Santiago de Compostela, A Coru~ na, Spain 2 Assistance Dog Association AEPA-Euskadi, 48014 Bilbao, Vizcaya, Spain 3 Dept. Matem atica Aplicada y CC, Universidad de Cantabria, Av. De los Castros s/n, 39005 Santander, Spain *Corresponding author: [email protected] Brain lateralization, the specialization of the left and right sides of the brain, has been shown to induce side preference in behavioral outcomes in a wide range of species. In dogs, behavioral lateralization has been reported in paw preference, tail-wagging, or head-turning responses to visual, acoustic, and emotive stimuli. Behavioral outcomes reflecting dog emotional state are of particular interest as animal welfare indicators (e.g., anticipating stress situations) for dog owners and handlers, provided these outcomes can be detected rapidly and unambiguously by simple observation. Although clear tailwagging biases have been observed in the laboratory, where dogs are kept still while recorded with a zenithal camera, these biases are difficult to check outside the lab (Quaranta et al., 2007; Whitfield, 2007). We wanted to know if tail-wagging biases can be detected in the field and to what extent this information can be useful. Data, therefore, consisted in video tracking of individual dogs from the dog handler’s viewpoint in day-to-day situations. Everyday scenarios were considered: at home, in the park, at work (assistance dogs) for 200 dogs. Visits to the veterinarian, a potential stressor, were specifically analyzed (29 dogs). We expected a clear left bias when the dog was asked to enter the clinic. Our results show that, outside the lab, tail-wagging asymmetries in daily situations do not allow us to infer the dog’s emotional state, the 15 angle bias obtained in the lab being not perceptible at all in the field. Only in extreme situations of dog reluctance, a clear and definitive lateral tail movement to the left was observed. Thus, dog handler attention should be focussed on body and calming signals, those being better indicators of the emotional state of a dog, although we cannot rule out that superior observational skills of owners who are highly familiar with a specific dog may establish a reliable link between tail movements and emotional states. Key words: tail-wagging; brain lateralization; fieldwork
Journal of Veterinary Behavior, Vol 6, No 1, January/February 2011
the way we treat and educate dogs and the way humans have to be respected. Second, dogs’ welfare is guaranteed along the activities, as dogs’ welfare is precisely the subject matter of the course, and dogs are always under the care and supervision of their owners (AEPA-Euskadi trainers) and are never left inside the prison. Third, to be present throughout the reintegration process (inside and outside the prison) reinforces the confidence, tranquillity and stability of the inmates. Key words: dog welfare; dog assisted activity; pro-social skills; prison inmates WOLF-PACK HUNTING STRATEGY: AN EMERGENT COLLECTIVE BEHAVIOR DESCRIBED BY A CLASSICAL ROBOTIC MODEL C. Muro1,*, R. Escobedo1,2, R.P. Coppinger3, L. Spector3,4 1 Assistance Dog Association AEPA-Euskadi, C/Pte. Deusto 7 - 48014 Bilbao, Vizcaya, Spain 2 Dept. of Applied Mathematics and Computational Sciences, University of Cantabria, 39005 Santander, Spain 3 School of Cognitive Science, Hampshire College, Amherst MA 01002, USA 4 Dept. of Computer Science, University of Massachusetts, Amherst MA 01003, USA *Corresponding author: [email protected] Wolf-pack social behaviors are considered highly organized social mechanisms in which a sophisticated communication system plays an essential role. Among these complex social interactions, wolf-pack hunting strategies are often presented as the proof that a social structure sustains the relation between pack members, and, still, that this social structure is based on hierarchical rules. After the advent of robotic science and artificial intelligence models of swarms, flocks and herds, complex behaviors are known to emerge from the combination of small sets of simple rules controlling the single behavior of each individual. In particular, multi-robot models have shown to be effective in describing capture processes often called hunts. A robot hunting model is presented in which two simple decentralized laws for the movement of each wolf-bot account for reproducing the main features of the wolfpack hunting ethogram: tracking the prey, carrying out the pursuit, encircling the prey and harassing it until the capture is considered over. Wolf-bots are all autonomous and indistinguishable from one another, therefore interchangeable–the geometrical position of the prey and of the other wolf-bots, especially those close to the prey, being the only information they need. Numerical simulations are carried out for multiple combinations of the parameters: pack size ranging from 2 to 20 members, different relative positions and speeds, etc. Prey movement is arbitrarily selected to be successively still, moving describing large circles, first with constant speed and after with positive or negative acceleration, and simulating an escaping movement.
The results show that hunting in packs is an emergent group behavior which does not necessarily rely on effective communication between the individuals participating in the hunt. With special emphasis, it is shown that no hierarchy is needed in the group to achieve the task properly. Key words: wolf-pack hunting ethogram; social emergent behavior; robotic model
HAPPY TAIL WAGGING: A LABORATORY ARTIFACT? LATERAL TAIL WAGGING IN THE FIELD Benigno Paz1, Ram on Escobedo2,3,* 1 Kns ediciones, 15780 Santiago de Compostela, A Coru~ na, Spain 2 Assistance Dog Association AEPA-Euskadi, 48014 Bilbao, Vizcaya, Spain 3 Dept. Matem atica Aplicada y CC, Universidad de Cantabria, Av. De los Castros s/n, 39005 Santander, Spain *Corresponding author: [email protected] Brain lateralization, the specialization of the left and right sides of the brain, has been shown to induce side preference in behavioral outcomes in a wide range of species. In dogs, behavioral lateralization has been reported in paw preference, tail-wagging, or head-turning responses to visual, acoustic, and emotive stimuli. Behavioral outcomes reflecting dog emotional state are of particular interest as animal welfare indicators (e.g., anticipating stress situations) for dog owners and handlers, provided these outcomes can be detected rapidly and unambiguously by simple observation. Although clear tailwagging biases have been observed in the laboratory, where dogs are kept still while recorded with a zenithal camera, these biases are difficult to check outside the lab (Quaranta et al., 2007; Whitfield, 2007). We wanted to know if tail-wagging biases can be detected in the field and to what extent this information can be useful. Data, therefore, consisted in video tracking of individual dogs from the dog handler’s viewpoint in day-to-day situations. Everyday scenarios were considered: at home, in the park, at work (assistance dogs) for 200 dogs. Visits to the veterinarian, a potential stressor, were specifically analyzed (29 dogs). We expected a clear left bias when the dog was asked to enter the clinic. Our results show that, outside the lab, tail-wagging asymmetries in daily situations do not allow us to infer the dog’s emotional state, the 15 angle bias obtained in the lab being not perceptible at all in the field. Only in extreme situations of dog reluctance, a clear and definitive lateral tail movement to the left was observed. Thus, dog handler attention should be focussed on body and calming signals, those being better indicators of the emotional state of a dog, although we cannot rule out that superior observational skills of owners who are highly familiar with a specific dog may establish a reliable link between tail movements and emotional states. Key words: tail-wagging; brain lateralization; fieldwork