Hoarding versus the immediate consumption of food among hamsters and gerbils

Behavioural Elsevier

Processes,

9 (1984) 3- 11

HOARDING

VERSUS THE IMMEDIATE

3

CONSUMPTION

OF FOOD AMONG HAMSTERS

AND GERBILS

RODERLCK WONG Department

of Psychology,

University

of British Columbia,

Vancouver

(Canada,

V6T lY7) (Accepted

20 August

1983)

ABSTRACT Hoarding versus the immediate consumption Wong, R., 1983. hamsters and gerbils. Behav. Processes 9: 3-11.

of food among

This project dealt with a comparative analysis of the effects of food The animals were deprivation on feeding and hoarding in hamsters and gerbils. given food in their home cage and their food intake was measured during a 30-min period after which they were transferred to an apparatus in which hoarding behaviour was assessed. The results indicated interesting species Whereas differences in the animals' reactions in the test situations. food-deprived gerbils ate more ,food than nondeprived gerbils, the food intake In the hoarding of hamsters was not significantly enhanced by deprivation. test, although significant differences were observed between deprived and nondeprived gerbils, the absolute level of hoarding in gerbils was very low in These comparison to that of hamsters tested under the same conditions. results suggest that hamsters and gerbils respond to challenges to their food reserves with different strategies.

INTRODUCTION Most animals

that are allowed

access

to food for a limited

time each day

consume

their usual daily amounts of food during

the limited period (Fabry,

1969).

This phenomenon

due to adaptability

infrequent gerbil

(Kutscher,

auratus)

of post-fast

1969).

In similar

reacts by displaying

that the hamster's

an adaptation (Silverman Although prodigious

literature

test situations anorexia

1982; Silverman noncompensatory

hoarder

observations

of food (Murphy,

on hoarding

suggest

It has been

1976).

of noncompensation

that Mesocricetus

1971), experimental

in the domesticated as not prolific

in that respect.

hamsters

comparison,

hoard more than when satiated.

@ 1984 Elsevier

Science

Publishers

B.V.

auratus

is a

studies of hoarding experimental

Rattus norvegicus,

Smith and Ross (1950) using a within-subject

0376-6357/84/$03.00

than hyperphagia

feeding may be due to hoarding,

are few when compared with the extensive

Beach (1950) regarded

the

(Mesocricetus

1976).

naturalistic

food-deprived,

rather

to brief

including

the hamster

and Zucker,

that can be linked to the phenomenon

and Zucker,

among hamsters

in a number of species

post-fast

(Borer et al., 1979; Rowland, suggested

hyperphagia

feedings has been observed

a species

that

An early study by indicated

that when

In that experiment

the

4

hamsters

were first tested under a restricted

consecutive

days and then given seven additional

feeding conditions.

phase and declined

of pellets hoarded

statistical

food deprivation

analysis

and hoarding

trials under ad lib

over test sessions.

phase,

weakens

merits

for seven

during the first two days

during the deprivation

than that during the satiation

inappropriate

hoarding

Hoarding was most pronounced

during the deprivation mean number greater

feeding schedule

Although

phase appeared

the

to be

the lack of counterbalancing

the conclusion.

and

Thus the issue of

further study with a more adequate

methodology. There have been few studies on hamster

hoarding

Ross (1950) paper and none of them involved studies,

Hammer

hoarding

material

day.

(1972) examined

the non-deprived

over test sessions

is consistent

prefer hoarding

The basic

objects

over plain chow pellets.

found a decline

in food hoarding

corresponded

food-hoarding

earlier studies. learning

and Blancheteau

To demonstrate

contrasted

the effects

reinforcement extinction addressed

theory.

dealt with the ontogeny of food-hoarding of a distinctive

with sexual maturity.

al. (1978) and Morin

and Fleming

in

(1982)

performance

as well as the

and Blancheteau

recent

in hamsters pattern

Launay's

paper was

theory such as the role of

and their relevance

another

hoarding

In this respect,

factors and food-hoarding

as a reinforcer

(PRF) training with continuous

the Launay

processes

However,

of

from that taken in

of hoarding

issues in animal learning association

to be highest.

Launay and Blancheteau

of runway

Basically,

in female

food intake, hoarding

the phenomenon

different

the efficacy

inter- and intra-trial

that the appearance

females,

They that their

(1'978) on the role

levels are expected

animals,

theory and frustration

endocrine

cycling

(1982) approached

(CRF) on the acquisition

to persisting

and Fleming

of partial reinforcement

of this response.

and observed

of eating and body weight

from a perspective

studies with food-sated

as

that non-deprived

in female hamsters.

on the day of estrous

that in normally

in hamsters

that

Estep et al. (1978) were concerned

cycle on hoarding

are lowest when estrogen

Launay

with

that are either sweet, sour, hard or shiny

in the regulation

It appears

Recently

(1969) indicate

nicely with those of Morin

of gonadal hormones

in

by the fifth

findings of the Hammer experiment

More recently,

of the estrous

and body weight

preference

in hoarding

by Smith and Ross.

hamsters.

hamster's

preference

with the effects

results

In one of these

a drop in relative

well an earlier one by Scelfo and Hammer hamsters

to the Smith and

and observed

This decline

reported

subsequent

food deprivation.

and his results (storing

observations

may be related

to sequential

paper by Launay

(1982)

indicate

food) coincides on the onset of

to suggestions

(1978) on the role of hormones

by Estep et

on this

behaviour. In the present experiment

we did a comparative

analysis

of the effects

of

5 food deprivation comparison

on feeding and hoarding

in hamsters

characteristics

of the hamster's

reactions

We used a procedure

that was a modification

(1974) for studying

the effects

gerbils.

The unique

were placed

in an apparatus

behaviour.

Although

the hoarding

and feeding in

for 30 min after which

for the assessment

behaviour,

1980).

These experimenters before

to eat prior to

data on food-deprived

found in gerbils

reasoned

the hoarding

because

were

rats

and

(Nyby & Thiessen,

that feeding their deprived

trial serves

it decreases

they

of hoarding

that the opportunity

(Morgan et al. 1943; Smith and Ross, 1950; Stellar

Similar results

1943).

immediately

that allowed

depress hoarding

Morgan,

spent hoarding

on hoarding

by hoarding.

by Nyby et al.

was that the animals were given

for feeding

one might suspect

test would

otherwise

of one developed

of amphetamine

A

the unique

to food deprivation

feature of this procedure

food in their home cage and tested

indicate

and gerbils.

of these two desert rodents was done to highlight

to optimize

subjects

the amount of time

the amount of time spent eating during

the

test period. In accounting deprivation, hoarding

for the hamsters'

Silverman

tendency

noncompensatory

and Zucker

is an adaptation

al., 1979; Rowland, deprived feeding

hamsters test.

1983; Silverman

would not differ

which

during

counterparts the hoarding

I could work.

the assertion

that the golden hamster

cheekpouches

al., 1983).

laboratory

is highly

specialized

level, this specialization

gerbils without

food deprivation laboratory

in hoarding

substantial

in seminatural

studies by Smith and Ross (1950) and Morin

differences

reason

procedure

it is difficult

that I designed

and test conditions

(1978) on

in these species.

comparison.

of

(1980) hints

in those experiments

to make a direct species

the present experiments.

outdoor

and Fleming

possible

greatly,

food hoarding

An examination

and those by Nyby et al. (1974) and Nyby and Thiessen

the experimental

food

volume of food (Etienne et

situations.

of hoarding

on

I drew upon

takes the form of

hamsters

in the magnitude

species material

and gerbil differences,

Nyby et al. (1973) had obseved

as well as in certain

food intake

In predicting

1969).

which can hold a considerable

However,

by domesticated settings

hamster

that

ones during the 30 min

should show greater

test, there was less substantial

In predicting

and that on the morphological internal

(Kutscher,

the present

work (Borer et

1976), I predicted

from deprived gerbils

hamster

strong

These authors

and I addressed

and Zucker,

deprived

In contrast,

than their deprived differences

experimentally,

On the basis of previous

to this issue.

following

that these animals'

linked to noncompensation.

did not deal with this suggestion experiments

feeding

(1976) proposed

at

Because vary

It is for this

EXPERIMENT

1

METHODS Subjects

acd Apparatus

The subjects

included

18 male Syrian golden hamsters

106-129 g, obtained

auratus),

These 90-100 day old animals were random-bred other

and of the HORFI

subjects were 18 male 100 day old Mongolian

unguiculatus)

bred in his laboratory.

g at the beginning

The room temperature

08,OO h and off at 20,OO h. of exactly

7.5 cm in diameter the hoarding plastic

cages (Carworth) with

The

(Meriones ranged

from 65 to 80 housed

Sanicel bedding

on

was set at 20 C, and the lights were on at test cages were plastic mouse

as the housing

A heavy

cages.

and 20 cm long was inserted

cage.

Ontario.

strain.

The animals were individually

The hoarding

the same dimensions

gerbils

Their body weights

of this experiment.

in 12 by 17 by '27 cm plastic mouse the floor.

(Mesocricetus

from the High Oak Ranch, Goodwood,

cages

cardboard

tube

into a hole cut at one end of

The other end of the cardboard

tube was plugged with a

cap and 30 Purina Lab Chow chunks weighing

about 2 g each were placed

in the far end of the tube.

Procedure Testing was done in late July. randomly

assigned

animals received deprivation daily

Half of the hamsters

to the food deprivation both food and water

consisted

while

ad lib throughout

of restricting

feeding period.

condition

and gerbils were

the animals' access

Water was available

the remaining Food

the experiment.

to all animals

to food to 30 min throughout

the

experiment. At 10,OO h Purina cage.

Chow chunks were weighed

The pellets were removed

determined.

Immediately

the Sanicel bedding and the animals

after

and placed in each animal's home

30 min, reweighed,

after the food was removed,

was transferred

from the home cage to the hoarding

were then given a 30min

hoarding

transferred

in order to reduce

the relative

apparatus.

Hoarding

was quantified

behaviour

of the adjoining

RESULTS

cardboard

tube.

trial.

novelty

The bedding

cage, was

of the hoarding

by counting

carried by the animals during the 30-min period

hoarding

and the consumption

the animals were weighed,

the number

of chunks

to the test cage from the end

All animals were given the feeding and

tests for five consecutive

days.

AND DISCUSSION

As expected

the body weight

of the food-deprived

was lower than that of the control hamsters test period, 1(1,64)

= 7.76, E < .Ol.

hamsters

(? = 109.98 g)

(? = 124.78 g) during

Similarly,

the 5-day

there was a significant

7 difference

between

g) and control the animals' significant

the body weight

gerbils

food intake during the 30-min difference

non-deprived difference

hamsters between

1.09 g), F(1,16) behaviour

= 23.03, E<

displayed

hamsters

(x = 0.36 pellets),

been given access

certainly

the experiments.

cage until

gerbils were removed

magnitude Thiessen

in the test apparatus

under exactly

much

Whereas

situation, hoarding

consistent

the

prior to

gerbils

that had

test, hoarded

gerbils hoarded

about 7 less

less than those used in the

our gerbils

they were

Plexiglas

tube, while our own

differences

for the differences

of the gerbils

studied

one, the interesting

test

in prior in the

in the Nyby and

fact is that hamsters

than gerbils when the animals were tested

conditions.

the low baseline

it appears

The other

gerbils were tested

their 30-min feeding

Although

would account

behaviour

gerbils had

did not have contact

tested.

Nyby and Thiessen's

apparatus.

amount of hoarding

behaviour

between

Nyby and Thiessen's

apparatus,

and the present

similar

Notwithstanding

experiment,

from their home cage following

of the hoarding experiment

greater

both rodents have been regarded

the hoarding

the time when

into the hoarding

showed a greater

(x = 0.11 pellets),

have not been considered

in their home cage, which had an adjoining

experience

gerbils

There are two major methodological

was in method of testing.

and then placed

as well as between

the non-deprived

hoarded

with the hoarding

the hoarding

difference

test while

(1980) experiment.

between

prior experience

significant

and non-deprived

that test.

gerbils

Nyby and Thiessen

with

Although

19801, direct comparisons

test conditions

to food for 1 h preceding

the 30-min

than 1 pellet during

differences

Although

(1969).

and non-deprived

.05,

In the Nyby and Thiessen

the present experiment.

Our deprived

Our food-deprived

(2 = 9.69 pellets)

and non-deprived

by Borer et

by Kutscher

deprived

differences.

= 5.37, E<

(Nyby C Thiessen,

under similar

during

(1976).

between

deprived

than among gerbils.

as natural hoarders two species

feeding

. 05, the magnitude of hoarding was considerably

= 6.82, E<

among hamsters

ones (ft =

of compensatory

and Zucker

species

between

.05, but a significant

feeding noted previously

differences

some interesting

were observed

no

with earlier observations

(1982) and Silverman

of

g) and

(!? = 0.85

= 1.29, E>

(i = 63.00

Analysis

test period indicated

The absence

(% = 2.60 pellets), 1(1,64)

deprived

pellets

.OOl.

the compensatory

.05.

(% = 1.93 g) and non-deprived

is consistent

of the hoarding

animals revealed differences

gerbils

gerbils

= 8.85, E<

the intake of deprived

(x = 0.61 g), 1(1,16)

in our hamsters

The analysis

2(1,64)

between

deprived

al. (1979), Rowland gerbils

level of food-deprived

(? = 70.36 g), F(1,64)

level of hoarding

that food deprivation

as it did with hamsters.

with those observed

by gerbils

has a facilitating In that respect

in our test

effect on their

our results

in gerbils by Nyby and Thiessen

are

(1980) and in

hamsters

Despite

by Smith and Ross (1950).

methodology

our earlier reservations

of the Smith and Ross experiment,

conclusion

that deprived hamsters

EXPERIMENT

2

Although

hoard more

the low level of hoarding

we now concur with their than non-deprived

displayed

by the gerbils

may be due to their relative

lack of exposure

may be due to their tendency

to "nest" in the region

the food.

In contrast

and deposited chewing

to hamsters

the pellets

on the cardboard

the tube. reverse

the structure

of the situation

in the home cage and observed whether end of the connecting pellets

transported

tube.

of the tube containing

spent more

in Experiment

in Experiment

2.

the animals would

time

to the end of

1 we decided

We placed transport

1 we compared

and non-deprived

1

another reason

the shredded material

As in Experiment

by deprived

in Experiment

food away from the tube

in their home cage, the gerbils tube and carrying

ones.

to the apparatus,

that transported

As a result of these observations

about the

to

the pellets them to the

the number of

animals.

METHODS Subjects

and Apparatus

We used the .same 18 male hamsters Experiment

1.

the beginning 77 g.

The body weights of the experiment

The home

and gerbils

of the hamsters while

that were studied ranged

in

from 98 g to 126 g at

those of the gerbils ranged

from 61 g to

and test cages were also the same as those previously

used.

Procedure We tested the animals During

feeding and watering

expetiments,

schedule.

that they were assigned At 10,OO h Purina cage.

10 days after they had completed

the period between

in Experiment

were placed in the hoarding counting

1.

chow chunks were weighed

apparatus.

and placed in each animal's home

30 min later and the animals were

During

the hoarding

cage and hoarding

animals were given the feeding

to it.

then placed

from their home

test Purina

behaviour

the number of chunks carried by the animals tube connected

1.

in the same intact groups

cage after the Sanicel bedding was transferred

cage to the hoarding

of the cardboard

Experiment

the animals on an ad lib.

We kept the animals

The chunks were reweighed

in the hoarding

we placed

chow chunks

was quantified

by

from the cage to the end

The test period was 30 min, and all

and hoarding

tests for five consecutive

days.

RESULTS AND DISCUSSION The food intake of deprived than that of control gerbils

gerbils

(!?= 1.54 g) was significantly

greater

(R = 0.80 g) during the 5-day period, 1(1,64)

=

9 25.11, E

<.OOl.

hamsters

In contrast

to the results

showed a significant

the control

animals

observation

of compensatory

finding

experimental

hamsters'

control

animals

and maintained

deprived

gerbils moved more pellets

(? = 0.22), 2(1,64) between

the hoarding

this

The

and a limited

feeding

the 30-min period

behaviour

revealed

deprived

than

than did non-deprived

of deprived (E >.05).

An examination

these conditions

and reversing

the structure

general

seem to have reduced

of the

Providing

1.

and

about the same them

of the test

level of hoarding.

the hoarding

relative

to their level in Experiment

activity

may also be due to their relative

1.

On

activity

However,

the deprived hamsters reduction

in hoarding

gerbils

(x = 3.44 chunks)

that the gerbils exhibited

the gerbils'

1,

there was no significant

as they did in Experiment

to facilitate

and non-deprived

As in Experiment

In contrast,

in the test apparatus

did little

between

(!? = 0.67)

< .02.

level of hoarding

the other hand,

food during

differences.

(? = 4.84 chunks) hamsters

with experience situation

species

= 6.61, E

levels of hoarding

low baseline

process.

with deprivation

differences

and gerbils revealed

absolute

this

was unexpected,

devoid of such experience.

hamsters

non-deprived

Although

to

that feeding behaviour

by a learning

them to ingest more

An analysis of the hoarding

difference

by hamsters

(1951) contention

prior experience

period may have caused

1, food-deprived

= 12.26, E < .OOl.

feeding behaviour

with Ghent's

is strengthened

of Experiment

in food intake (3 = 0.47 g) relative

(x = 0.21 g), 1(1,64)

is consistent

(in rats)

increase

of

this

increase

in

food intake during the feeding test.

GENERAL DISCUSSION Comparisons indicate

between

gerbils

that these rodents

deprivation.

and hamsters

exhibit

When given access

under the same test conditions

different

behavioural

period of time following

deprivation,

this period

and when placed in an environment

than normal,

given an opportunity such activity.

to hoard

In contrast,

cage for food consumption

gerbils

show greater

when hamsters

following

tested in the hoarding

substantially conditions.

more hoarding Thus it appears

to their food reserves primarily

by displaving

while hamsters rather

were initially

deprivation,

where

during

they are

low level of

tested in their home

they showed about the same However, when

following

behaviour

than did gerbils under the same test

that gerbils

with different compensatory

the feeding

the hamsters

apparatus

and hamsters

strategies.

feeding activities.

test, they showed

respond

to challenges

Gerbils react to privation

feeding when permitted

react to the state of depletion

than greater

to food

consumption

the food, they show a relatively

level of feeding as they did when not deprived. were

reactions

to food in their home cage for a limited

by exhibiting

access

to food

greater hoarding

10 In their work with rats, Herberg Stephens

(1977) demonstrated

per se but rather

and Blundell

that hoarding

to body weight

loss.

(1970) and Her-berg and

is not related

to food deprivation

They found that rats hoard only when

their body weight was decreased by more than ten per cent and argued hoarding

behaviour

regulation

fulfills

of body weight.

the conditions Fantino

of a defence response

and Cabanac

based on their results with rats indicating proportional of hamsters 1 revealed mch

to body weight

(12%) and gerbils

higher

(11%) during between

level of hoarding

Yet the hamsters

than gerbils but ate less.

rodents,

it would be necessary

to test them under different

behaviour

Although

the absolute

was greater the former. behaviour

food-hoarding

level of hoarding

It appears

behaviour

in deprived

difference

test, this change

In this respect,

greater

only in gerbils.

another

hamsters

were evident

show compensatory

in motive

we have

food intake in

and non-deprived

of deprivation

that when deprived hamsters

prior to the hoarding activities.

these

levels of weight

for feeding and hoarding

produced

than those in gerbils, no effects

their hoarding species

were retested

2, food deprivation

both species and facilitated

equation with

This will be the basis of a future experiment.

and hamsters

in Experiment

and Cabanac

showed a

In order to perform

of the Fantino

recovery.

loss

the 5-day test period of Experiment

these rodents.

test of the relevance

When the gerbils

was

of the body weight

a proper

loss and subsequent

an equation

that the amount hoarded

An examination

decrease.

little difference

(1980) developed

that

in the

in

feeding

state reduces interesting

in behaviour.

ACKNOWLEDGEMENTS I thank Patricia Fairey for her help in conducting the experiments and Wayne Jones for the statistical analysis of the data. This research was aided by grant 67-0247 from the Natural Sciences and Engineering Research Council of Canada. REFERENCES The snark was a boojum. Beach, F.A., 1950. Amer. Psychol., 5: 115-124. Borer, K.T., Rowland, N., Mircw, A., Borer, R.C. and Kelch, R.P., 1979. Physiological and behavioral responses to starvation in he golden hamster. Am. J. Physiol., 236: E105-E112. Estep, D.Q., Lanier, D.L. and Dewsbury, D.A., 1978. Variation of food hoarding with the estrous cycle of Syrian golden hamsters (Mesocricetus auratus). Harm. Behav., 11: 259-263. Etienne, A.S., Emmanuelli, E. and Zinder, M., 1982. Ontogeny of hoarding in the golden hamster: The development of motor patterns and their sequential Devel. Psychobiol., 15: 33-45. coordination. Etienne, A.S., Matathia, R., Emmanuelli, E., Zinder, M. and de Caprona, D.C., The sequential organization of hoarding and its ontogeny in the 1983. Behaviour, 83: 80-112. golden hamster. Feeding pattern and nutritional adaptations. London: Fabry, P. 1969. Butterworths. Fantino, F. and Cabanac, M., 1980. Body weight regulation with a proportional hoarding response in the rat. Physiol. Behav., 24: 939-942.

Ghent, L., 1957. Some effects of deprivation on eating and drinking. J. Comp. Physiol. Psychol., 50: 172-176. Hammer, L.R., 1972. Further hoarding preferences in hamsters. Psychon. Sci., 26: 139-140. Non-interaction of ventromedial and Herberg, L.J. and Blundell, J.E., 1970. lateral hypothalamic mechanisms in the regulation of feeding and hoarding behaviour in the rat. Q. J. Exp. Psychol., 22: 133-141. Interaction of hunger and thirst in Herberg, L.J. and Stephens, D-N., 1977. the motivational arousal underlying hoarding behaviour in the rat. J. Camp. Physiol. Psychol., 91: 359-364. Species differences in the interaction of feeding and Kutscher, C.L. 1969. Annals of the New York Academy of Sciences, 157, 539-551. drinking. Cntoge/nkse du comportement d'amassement chez le hamster. Launay, M. 1982. Biol. Behav., 7: l-15. Effects of inter-trial interval length Launay, M. and Blancheteau, M. 1982. on food-hoarding partial reinforcement of running behavior in the golden hamster. Behav. Processes, 7: 341-352. Food deprivation and hoarding Morgan, C.T., Stellar, E. and Johnson, 0. 1943. in rats. J. Comp. Psychol., 35: 275-285. Morin, L.P. and Fleming, A.S. 1978. Variation of food intake and body weight with estrous cycle, ovariectomy, and estradiol benzoate treatment in hamsters (Mesocricetus auratus). J. Camp. Physiol. Psychol., 92: l-6. Natural history of the Syrian golden hamster - A Murphy, M.R., 1971. reconnaisance expedition. Am. Zool., 11: 632. Nyby, J., Belknap, J.K. and Thiessen, D.D., 1974. The effects of d- and lamphetamine upen hoarding behavior and feeding in the Mongolian gerbil (Meriones unguiculatus). Physiol. Psychol., 2: 497-499. Food hoarding in the Mongolian gerbil Nyby, J. and Thiessen, D.D., 1980. Behav. Neur. Biol., (Meriones unguiculatus): Effects of food deprivation. 30, 39-48. Failure by deprived hamsters to increase food intake: Rowland, N., 1982. Some behavioral and physiological determinants. J. Camp. Physiol. Psychol., 96, 591-603. Stimulus preferences in hoarding. Scelfo, L.M. and Hammer, L.R., 1969. Psychon. Sci., 17: 155-156. Silverman, H.J. and Zucker, I., 1976. Absence of post-fast food compensation in the golden hamster (Mesocricetus auratus). Physiol. Behav., 17: 271-285. Smith, W.I. and Ross, S., 1950. Hoarding behavior in the hamster. J. Genet. Psychol., 77: 211-215. Stellar, E. and Morgan, C.T., 1943. The roles of experience and deprivation in the onset of hoarding behavior in the rat. J. Camp. Psychol., 36: 47-55.