Seasonal change in terrestriality of chimpanzees in relation to microclimate in the tropical forest

Abstract

Seasonal change in time spent for terrestrial behavior of chimpanzees was investigated from the viewpoint of the distribution of food and microclimate in the forest at Bossou, Guinea, West Africa. Daily and monthly data for activity budgets of three focal animals, climatic variables in the forest, and indices of fruit availability and distribution of fruit-bearing trees were estimated and analyzed. Mean activity budgets calculated by monthly means were 23.4% for terrestrial behavior (range, 2.9% in August to 42.1% in November) and 76.6% for arboreal behavior. Chimpanzees spent more time on the ground in warm or dry months. Chimpanzees also spent less time in trees in months with high fruit production (trees of diameter at breast height >/=10 cm). The daily percentage of terrestrial behavior showed a positive correlation with maximum temperature and a negative correlation with the minimum humidity of the day. Only maximum temperature of the observation day influenced time spent on the ground significantly, as analyzed by generalized linear models (GLZ), which included all variables (fruit production, distribution of fruit-bearing trees, and climatic variables). It was concluded that the reason why arboreal behavior increased in the rainy season was not owing to the vertical distribution of food, but rather in order to reduce thermoregulation costs by resting in trees during cool periods and taking advantage of the vertical structure of the microclimate in the tropical forest (i.e., higher temperatures in higher positions).

Assessing the effects of cognitive experiments on the welfare of captive chimpanzees (Pan troglodytes) by direct comparison of activity budget between wild and captive chimpanzees

“…Our results for the Bossou activity budgets were within the range of those in previous studies on activity budget in Bossou chimpanzees [Hockings et al, 2009;Takemoto, 2004;Yamakoshi, 1998]. Feeding rhythm was also similar to that in a previous report [Yamakoshi, 1998].…”

“…Even at the same research site, the activity budgets differed in different report. In Bossou, feeding time was about 40% in Yamakoshi [1998], 25.6% in Takemoto [2004], and 22.5 % in Hockings et al [2009]. Therefore, using the data that were collected using different methodologies can cause problems in analyzing the data and interpreting the results.…”

Molecular analyses of the intestinal microbiota of chimpanzees in the wild and in captivity

“…[Ushida et al, 2006] to fulfill their nutritional requirement for minerals. The daily consumption of these plant materials depends on the accessibility of the food [Takemoto, 2004]. In contrast to wild conditions, the feeding of animals in captivity is highly controlled, and chimpanzees regularly consume a commercial monkey chow supplemented with various kinds vegetables and fruits.…”

“…), musanga (Musanga cecropioides), and spondia (Spondias mombin). However, in the rainy season the consumption of fruit is limited compared to that in the dry season [Takemoto, 2004;Yamakoshi, 1998]. The chimpanzees often consumed gum exudates of Albizia spp.…”

Time and distribution: a model of ape biogeography

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