Adapting Methodology Used on Captive Subjects for Estimating Gut Passage Time in Wild Monkeys

Abstract

Gut passage time of food has consequences for primate digestive strategies, which subsequently affect seed dispersal. Seed dispersal models are critical in understanding plant population and community dynamics through estimation of seed dispersal distances, combining movement data with gut passage times. Thus, developing methods to collect in situ data on gut passage time are of great importance. Here we present a first attempt to develop an in situ study of gut passage time in an arboreal forest guenon, the samango monkey (Cercopithecus albogularis schwarzi) in the Soutpansberg Mountains, South Africa. Cercopithecus spp. consume large proportions of fruit and are important seed dispersers. However, previous studies on gut passage times have been conducted only on captive Cercopithecusspp. subjects, where movement is restricted, and diets are generally dissimilar to those observed in the wild. Using artificial digestive markers, we targeted provisioning of a male and a female samango monkey 4 times over 3 and 4 days, respectively. We followed the focal subjects from dawn until dusk following each feeding event, collecting faecal samples and recording the date and time of deposition and the number of markers found in each faecal sample. We recovered 6.61 ± 4 and 13 ± 9% of markers from the male and the female, respectively, and were able to estimate a gut passage window of 16.63–25.12 h from 3 of the 8 trials. We discuss methodological issues to help future researchers to develop in situ studies on gut passage times.

The effect of lizards on the dispersal and germination of Capparis spinosa (Capparaceae)

“…DRTs are reported to directly impact food digestibility, which probably depends on the gut volumes and food intakes of animals [31]. A number of studies have shown that DRTs are quite different among diverse animals; the DRT of monkeys was found to be 16-25 h [32], that of tortoises was 6-28 days [13], that of frugivorous birds was 15-45 minutes [33], and those of ruminants including cattle [34], elands [35] and horses [36] were generally 70-90 h, 45-70 h and 25-35 h, respectively. In this study, feeding experiments were conducted to examine the effects of age and food type on food intake rates and DRTs using captive T. roborowskii specimens.…”