No abstract

We observed a period of famine in the lowland tropical rain forest of Sabah, Malaysia from August 1999 to September 2000. All six Malayan sun bears (Helarctos malayanus) that were captured and radio-collared were in poor physical condition, and two were later found dead. The physical condition of bearded pigs (Sus barbatus) that were captured, observed or photographed by camera traps also revealed that the pigs were in various stages of emaciation and starvation. We surmise that the famine resulted from prolonged scarcity of fruit during an intermast interval in the study area. These phenomena of emaciated animals and fruit scarcity have also been reported from other areas of Borneo. Lowland tropical rain-forest trees of Borneo display supra-annual synchronized general fruiting. We believe that the starvation we observed and the generally low density of large animals in Borneo forests is a consequence of a history of prolonged food scarcity during non-general-fruiting years, but may be accentuated by anthropogenic factors such as forest fragmentation, selective logging, and reduced density of fig trees in logged forests.

We examine the effect of total annual food abundance and seasonal availability on the biomass and species richness for frugivorous primates on three continents (n=16 sites) by data on fruit fall. We reveal that the best‐fit models for predicting primate biomass include total annual fruit fall (positive), seasonality (negative) and biogeography (Old World>New World and mainland>island) and that these factors explain 56–67% of the variation. For the number of species, the best‐fit models include seasonality (negative) and biogeography (Old World>New World and mainland>island) but not total annual fruit fall. Annual temperature has additional effects on primate biomass when the effects of fruits and biogeography are controlled, but there is no such effect on species richness. The present results indicate that, measured on local scales, primate biomass and number of species is affected by the seasonal variation in food availability.

Facial mimicry is a central feature of human social interactions. Although it has been evidenced in other mammals, no study has yet shown that this phenomenon can reach the level of precision seem in humans and gorillas. Here, we studied the facial complexity of group-housed sun bears, a typically solitary species, with special focus on testing for exact facial mimicry. Our results provided evidence that the bears have the ability to mimic the expressions of their conspecifics and that they do so by matching the exact facial variants they interact with. In addition, the data showed the bears produced the open-mouth faces predominantly when they received the recipient’s attention, suggesting a degree of social sensitivity. Our finding questions the relationship between communicative complexity and social complexity, and suggests the possibility that the capacity for complex facial communication is phylogenetically more widespread than previously thought.

30As large areas of forest are lost throughout the tropics, prime habitat of many species 31 decline and become fragmented. The island of Borneo is a prime example, with accelerated 32 clearing of forests primarily for oil palm expansion. Borneo's forests are an important stronghold 33 for the conservation of the sun bear (Helarctos malayanus), but it is unclear how habitat 34 reduction and fragmentation is affecting this frugivore. We used camera traps and sign surveys to 35 understand patterns of sun bear habitat use in a matrix of fragmented forests and extensive oil 36 palm development, which has existed as such for >15 years: the Lower Kinabatangan floodplain 37 in Sabah, Malaysian Borneo. Within these small forest fragments, squeezed between a major 38 river and oil palm plantations, bears exhibited selection for areas farther from human activity 39 (forest edges, river boat traffic, and buildings), and were rarely active during the day, 40 demonstrating both spatial and temporal avoidance of potential human-related threats. They 41 selected large trees to feed and rest, and also exploited adjacent plantations to feed on oil palm 42 fruits. We conclude that even relatively small forest fragments (~2,000 ha) within large 43 agricultural landscapes can be important for sun bears. Our research highlights the remarkable 44 adaptations this species has employed to persist in a drastically modified landscape. 45 3 46 habitat use 47 111 the floodplain. Besides sun bears, large mammal species present in the landscape include the 112 Bornean orangutan (Pongo pygmaeus), Asian elephant (Elephas maximus), proboscis monkey 113 (Nasalis larvatus), and Sunda clouded leopard (Neofelis diardi). 114 6 2.2 Data collection 115 2.2.1 Habitat use 116 We used the detection of sun bears through camera traps as a primary measure of bear 117 habitat use in the Lower Kinabatangan. The primary goal of the camera trapping was to estimate 118 the density of Sunda clouded leopards in the region. As such, the location and method of 119 deployment was done to maximize the detections of clouded leopards; sun bear photos were non-120 target data. We deployed Reconyx PC800 and HC500 infrared camera traps (Reconyx Inc., 121 Holmen, Wisconsin, USA) at 77 different sites along riparian trails, forest trails, and ridgelines 122 (Figure 1). We secured camera traps to trees, 40-50 cm off the ground, with an average distance 123 of 1.22 km between adjacent sites (Ross et al. 2013). Cameras recorded the time and date of 124 every photographic capture. We checked camera sites at intervals of 30-80 days to check their 125 condition, replace batteries, and change memory cards. For each camera site, we divided the 126 sampling period into 44 weekly occasions from June 2013 until April 2014. Each occasion 127 represented a sun bear detection (1) or non-detection (0) event. We only considered independent 128 detections at each site, which we defined as photographs at least 24 hours apart. 129 We used the detection of sun bear sign as a second measure...