Abstract We aimed to ascertain the environmental determinants of the diets of Japanese macaques M acaca fuscata in relation to geographical variables (latitude and elevation) and environmental variables [annual rainfall, mean temperature, snow characteristics and normalized difference vegetation index ( NDVI ), a proxy for primary productivity] We collected dietary data from the entire range of Japanese macaques (29 study sites) and extracted each dietary component to determine spatial patterns over the species' range and between forest types. We then conducted model selection to identify the environmental determinants of staple diets and dietary diversity. Japanese macaques' diets were mainly composed of 1) foliage, 2) fruits and seeds, and 3) bark and leaf buds, throughout the entire range. Percentages of bark and buds were greater in deciduous forests than in evergreen forests; significant differences in the proportions of the other two major components and in dietary diversity were not observed in different forest types. Macaques inhabiting forests with higher NDVI and with less snow fed more on fruits and seeds, and a high dietary diversity was observed. In snowy forests, macaques inhabiting higher elevation fed more on foliage, while those inhabiting lower elevations fed mainly on bark and buds. When studying spatial patterns in the feeding behaviour of mammals, both environmental and geographical variables should be treated equally since the effect of environmental variables may be independent of the effect of geographical variables. In addition, more emphasis should be placed on snow characteristics, because snow cover leads to decreased availability of terrestrial food items and to increased energy costs (for locomotion and body temperature regulation), which can affect feeding behaviour and dietary diversity.
A field survey was conducted in Pangandaran Nature Reserve (PNR), West Java, Indonesia between 2011 and 2015, during which fresh carcasses of wild mammals were collected. Body sizes of these carcasses were performed. This paper reports relevant data for future applications.
Abstract The dietary composition of primates is often affected by the availability of food, as well as seasonal variations within their habitat. This study presents quantitative data on the feeding behavior of wild silvery lutungs ( Trachypithecus cristatus ) inhabiting a coastal forest in West Sumatra, Indonesia. This research emphasizes the relationship between food availability and the way this changes by season. Feeding strategies of these primates was also examined. Feeding behavior of a group of wild silvery lutungs was observed for 12 months from August 2018 to July 2019, with a total observation time of 482 hours. We recorded 74 items from 37 different plant species that were included in the lutungs’ diet. Nineteen out of 37 plant species comprised > 1% of the lutung’s annual diet. They can therefore be considered the main plant food sources for the lutungs. The lutungs mainly fed on young leaves (68.3%). However, during certain months, both ripe and unripe fruit formed a major part of their diet. Plant part-based analyses showed a negative correlation between the availability of young leaves and ripe fruit feeding. Plant species-based analyses revealed few significant positive relationships between the feeding percentages of the main dietary items (mainly young leaves) and their availability. This implies that young leaves and ripe fruit were both the preferred and the fallback foods. This also indicates that lutung activity, ranging patterns, and activity at the study site are affected mainly by food distribution and availability. Further research is needed to increase the understanding of Asian colobine feeding strategies, feeding patterns, and food resource characteristics.
Food availability varies seasonally for wild animals, and body weight fluctuates accordingly in the wild. In contrast, controlling availability of diet under captive condition is difficult from keepers' standpoint, and monotonous diet often causes health problems in captive animals. We evaluated the effects of a seasonally controlled diet on body weight of captive Japanese macaques (Macaca fuscata) in an outside enclosure at Ueno Zoo, Tokyo, Japan. We fed a high-energy diet in spring and fall, and a more restricted diet in summer and winter for 3 years (2011-2013). Seasonal changes in body weight were similar to those that occur in wild macaques: for both sexes, body weight was higher in spring and fall and lower in winter. A decrease in body weight between fall and winter occurred only in adults, which implied that reducing dietary intake in winter had a more severe effect on adults than on juveniles. Different from wild populations, the body weight of captive macaques did not decrease between spring and summer, which we attributed to a lack of movement within the enclosure and to excess energy intake in summer. In addition to controlling dietary composition, providing large enclosure with complex structure and making efforts of giving unpredictability in feeding are necessary to motivate the captive animals to be more active, which would cause the macaques to show seasonal change in body weight, which is found in wild.
Abstract Primate’s time budgets are the important aspect to investigate their ecological influences in their habitat. This study collected data on daily activities in a group of silvery lutung (Trachypithecus cristatus) in coastal forest habitat at Gunung Padang, West Sumatra, Indonesia from August 2018 – July 2019, using instantaneous scan sampling method with 10-min intervals. This study analyzed the activity of wild silvery lutungs in study site, with emphasis on the age-sex differences and montly changes in their activity budget. This group spent most of time resting in their daily activity (average 47.50% of the total daytime resting), then followed by moving, feeding, grooming and other activities (conflict, nursing, urinating-defecating, playing, etc.). Resting peaked simultaneously in the morning and peaked back in the afternoon while moving and feeding decreased in this period. Their time budgets showed significant monthly variation: they spent a higher value of time feeding from September - Oktober 2018. They also differed among different sex-age classes: nursing females spent more time for actively moving, whereas adult male and single females devoted more time to resting, feeding, and grooming. These differences in their time budgets may reflect fundamental differences in reproductive biology, parental investment and development among the different age-sex classes.
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