Diverse diets and high-sugar foraging preferences: foraging criterion in
low altitude primates
Abstract
Nutrient composition and food availability determine food choices and
foraging strategies of animals. Altitude affects species distribution
and food availability, whereas primate food needs increase with body
size. However, the mechanism of food selection in large primates at low
altitudes requires further investigation. As the largest species in the
genus Macaca, the Tibetan macaque (Macaca thibetana) has sophisticated
foraging strategies. In this study, we researched a group of 29 wild
Tibetan macaques (Tianhu Mountain Group) that live in a low-altitude
area around Mt. Huangshan, Anhui Province, China. We used instantaneous
and scan sampling for observing the foraging behavior of these macaques
from September 2020 to August 2021. We recorded the dietary composition
and food availability, compared the nutrient content of staple food and
non-food items, and analyzed the role of key nutrients in food
selection. We found that Tibetan macaques forage on 111 plants belonging
to 93 genera and 55 families. The food types included 52.5% fruits,
17.0% mature leaves, 6.3% young leaves, 1.9% stems, 4.5% flowers,
14.4% bamboo shoots, 1.3% tender shoots, and 2.1% other. Tibetan
macaques forage for a maximum total of 76 plant species during spring.
However, dietary diversity was highest during summer (H’=3.052). Monthly
fruit consumption was positively correlated with food availability.
Staple foods are lower in fiber and tannins than non-foods. In addition,
there was a positive correlation between the time spent foraging for
specific foods and sugar content of the food. The results showed that
the plant species and food types fed by Tibetan macaques were diverse,
and their foraging strategies varied seasonally. Our findings confirm
the effect of nutrients on food choice in Tibetan macaques, highlighting
the importance of sugar in their food choices and suggesting that the
foraging behavior of Tibetan macaques is highly flexible and adaptive.