Skip to main content
Open Access Publications from the University of California


The International Journal of Comparative Psychology is sponsored by the International Society for Comparative Psychology. It is a peer-reviewed open-access digital journal that publishes studies on the evolution and development of behavior in all animal species. It accepts research articles and reviews, letters and audiovisual submissions.

Volume 9, Issue 3, 1996


Temporal Characteristics of Grooming in an Open Field in Two Strains of Rats


temporal characteristics of grooming in an open field were studied in rats from two different genotypes (NR, brown Norway rats bred from an original wild stock and KM, Krushinsky-Molodkina albino rats selectively bred for audiogenic seizure susceptibility). The measures of grooming recorded were time of onset of any grooming activity, duration and number of grooming episodes and total time spent grooming during successive 3-min intervals over a total 12-min period. The results demonstrated that grooming episodes of different durations displayed different features across the course the test. Grooming was minimal in the first minutes of the test and the longest grooming episodes were observed after the sixth minute in most of the rats. The number and proportion of prolonged episodes (over 21 s in duration)increased over time. Short-duration episodes (1-3 s) were not connected with the specific stage of the test and/or the decrease in locomotion. The scores of grooming duration were higher in NR in comparison to the KM rats. No significant effects were found for strain and sex for total numbers of grooming episodes.

Temporal Patterning of Oral Stereotypies in Restricted-fed Fowls: 1. Investigations with a Sibgle Daily Meal


two experiments, 24 immature female broiler breeder fowls housed in two 12-cage battery units in identical rooms received a single daily ration which they ate in 10 min, according to a programme of food restriction. From regular 15-min videorecordings, measurements were made of times spent in mutually exclusive activities (sitting, standing, head out, pacing, preening, object pecking, drinker activity). In Experiment 1, feeding time was 09.00 h in one room and 13.00 h in the other, and all birds were videorecorded in every hour of the (14-h) photoperiod on two lternate days. Differences in behaviour before and after feeding were independent of feeding time. In both rooms, head out and pacing increased before feeding, and object pecking and drinker activity (oral stereotypies) commenced immediately afterwards and then declined. Individual variation in the oral stereotypies was significant, and individuals' mean levels of both stereotypies together were consistent on the two days, but their hourly patterns were less so. Experiment 2 tested the notion of homeostatic control of oral stereotypies, by feeding all birds at 09.00 h and measuring their responses to removal of drinkers and empty feeders (main targets of the stereotypies) for either 0, 1.5 or 3 h before 15.00 h. Each cage tier received each treatment once, over three alternate days when all birds were recorded on video between 12.00 and 18.00 h (lights ofQ. During removal of feeders and drinkers, partial suppression of object pecking and total suppression of drinker activity were balanced by corresponding increases in sitting, head out and preening. After the return of feeders and drinkers, preening declined and both stereotypies showed evidence of post-inhibitory rebound, but there was no difference between 1.5 and 3 h removal treatments. The results concur with earlier evidence  indicating that preening can substitute with oral stereotypies, and it is suggested they may demonstrate homeostasis in total (substitutable) oral activity over the whole test. Conceivably, homeostasis of arousal may underlie changes in broiler breeder behaviour before and after feeding time.

Temporal Patterning of Oral Stereotypies in Restricted-fed Fowls: 2. Investigations with a Single Daily Meal

Expression of oral stereotypies directed at the drinker (drinking) empty feeder (pecking), by young, caged, restricted-fed broiler breeder fowls, investigated in three experiments in which either the frequency of feeding or meal as varied. Behaviour was measured from regular 15-min videorecordings.  Experiment 1, birds were provided with either one (lA), two (IB) or four meals of 5 g in the morning, and a single balance meal in the afternoon. caused increases in drinking and pecking, compared with lA and IB, but effects meal number and the total weight of food eaten during testing were In Experiment 2, birds were provided with four meals of equal size in the morning,  either 1.5, 1 or 0.5 hr intervals, with a balance meal in the afternoon in the first only. There was no difference among these treatments in drinking or pecking at time, and neither stereotypy responded to variation in inter-feeding interval length the ways predicted by two alternative theoretical models, constructed for from Experiment 1, and a 1 and 2, indicated that both stereotypies were correlated meal size and/or the total amount eaten during testing. In Experiment 3, birds provided with two meals (only) of unequal size at 09.00 and 12.00 h, conditioned to receiving either the large meal (32 g) first, the small meal (8 g) first, and small meals in random order. The main finding was that pecking from the first to the third hour after the small meal only when the small meal first, and did not do so after the large meal. This suggests that the rate at stereotyped pecking declines after eating may depend on the amount that is eaten.