Rc. Kirkpatrick et al., Digestion of selected foods by Yunnan snub-nosed monkey Rhinopithecus bieti (Colobinae), AM J P ANTH, 114(2), 2001, pp. 156-162
Three digestion trials were conducted to quantify aspects of digestive phys
iology in the Yunnan snub-nosed monkey Rhinopithecus bieti, a foregut ferme
nter that feeds primarily on lichens. Mean retention time (MRT, the average
time plastic markers spent in the animal) had a mean estimate of 47 hr (n
= 3) with high variability between trials (standard deviation = 17 hr). Rec
ently captured animals, presumably with gut flora and digestive physiology
close to wild animals, had a longer retention time than did long-term capti
ves, although lack. of standardization across trials (such as in activity l
evel) confounds analysis. Apparent digestibilities for dry matter (71-80%)
were in line with other studies of colobine digestion, but fall below those
of ruminant ungulates feeding on lichens. Fecal analysis accurately determ
ined the relative proportions of leaves vs. lichens in diets; mature leaves
and lichens were not nutritional equivalents but appeared to be physiologi
cal equivalents in terms of digest passage. Fecal analysis does not, howeve
r, accurately determine the relative proportions of food types with differe
nt digestibilities, such as fruit vs, leaves. (C) 2001 Wiley-Liss, Inc.