Kc. Baker et Sp. Easley, AN ANALYSIS OF REGURGITATION AND REINGESTION IN CAPTIVE CHIMPANZEES, Applied animal behaviour science, 49(4), 1996, pp. 403-415
The abnormal behavioral. pattern of regurgitation and reingestion (R/R
) is poorly understood in chimpanzees (Pan troglodytes). This study as
sesses R/R in 13 indoor-housed chimpanzees living in pairs and trios.
Focal animal sampling data were used to calculate scores for R/R, two
other classes of abnormal behavior (abnormal behaviors with oral compo
nents and those without oral components), and affiliative social behav
ior. R/R was observed in 85% of study subjects, an elevated proportion
in comparison to a previously published survey of captive chimpanzee
populations. Contexts and temporal patterns of R/R suggest that detect
ion of this behavior may in many cases require observations outside of
daily management routines. Social disturbances did not elicit this be
havior. Statistical tests showed no relationship between individual di
fferences in R/R rates and rates of other abnormal behavior classes, t
ime engaged in affiliative behaviors, number of cagemates or housing h
istory; nor were sex differences detected. Meal composition was not fo
und to effect the time devoted to R/R. Statistical tests did show a st
rong positive relationship between rates of R/R and elapsed time since
feeding. These results suggest that increasing meal frequency or prov
iding consistently available edible material may prove more broadly ef
fective than altering meal composition. Temporal distributions of R/R
differed from those of abnormal behaviors, suggesting that factors suc
h as boredom, hunger or other sources of stress may differentially aff
ect the expression of various classes of abnormal behavior.