Regurgitation and reingestion (R/R) is a potentially self-injurious behaviour in nonhuman primates and is a common problem among captive primates. The temporal and contextual distribution of R/R and its relationship to diet were assessed in 13 indoor-housed chimpanzees living in pairs and trios. A focal animal, instantaneous point-sampling technique was used to record behaviour from a previously developed ethogram of 33 behaviours and the data obtained were used to calculate scores for R/R, two other classes of abnormal behaviour (abnormal behaviours without and with oral components), and affiliative social behavior. R/R was observed in 85% of study subjects, an elevated proportion in comparison with a previously published survey of captive chimpanzee populations. Contexts and temporal patterns of R/R suggest that detection of this behavior may in many cases require observations outside of daily management routines. Social disturbances did not elicit this behavior. Statistical tests showed no relationship between individual differences in R/R rates and rates of other abnormal behaviour classes, time engaged in affiliative behaviours, number of cagemates or housing history; nor were sex differences detected. Meal composition did not effect the time devoted to R/R. Statistical tests showed a strong positive relationship between rates of R/R and elapsed time since feeding. The results suggest that increasing meal frequency or constantly providing available edible material may prove more effective than altering meal composition. Temporal distributions of R/R differed from those of abnormal behaviours, suggesting that factors such as boredom, hunger or other sources of stress may differentially affect the expression of various classes of abnormal behaviour.
|Publication Title||Applied Animal Behaviour Science|
|Author Address||Yerkes Regional Primate Research Center, Emory University, Atlanta, GA 30322, USA.|
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