Selection of sleeping trees in pileated gibbons (Hylobates pileatus)

Abstract

Selection and use patterns of sleeping sites in nonhuman primates are suggested to have multiple functions, such as predation avoidance, but they might be further affected by range defense as well as foraging constraints or other factors. Here, we investigate sleeping tree selection by the male and female members of one group of pileated gibbons (Hylobates pileatus) at Khao Ang Rue Nai Wildlife Sanctuary, Thailand. Data were collected on 113 nights, between September 2006 and January 2009, yielding data on 201 sleeping tree choices (107 by the female and 94 by the male) and on the characteristics of 71 individual sleeping trees. Each sleeping tree and all trees > or =40 cm diameter at breast height (DBH) in the home range were assessed (height, DBH, canopy structure, liana load) and mapped using a GPS. The gibbons preferentially selected tall (mean=38.5 m), emergent trees without lianas. The majority of the sleeping trees (53.5%) were used only once and consecutive reuse was rare (9.5%). Sleeping trees were closer to the last feeding tree of the evening than to the first feeding tree in the morning, and sleeping trees were located in the overlap areas with neighbors less often than expected based on time spent in these areas. These results suggest avoidance of predators as the main factor influencing sleeping tree selection in pileated gibbons. However, other non-mutually exclusive factors may be involved as well.

Population mapping of gibbons in Kalimantan, Indonesia: correlates of gibbon density and vegetation across the species’ range

“…They also found some weak indication that the probability of occupancy may in crease with tree diversity. Tree diversity has been found to be an important habitat requirement of gibbons (Caldecott 1980, Fan & Jiang 2008, Phoonjampa et al 2010. Low tree-species diversity in the survey areas indicates that some inter-group resource competition may occur and that the probability of gibbon occupancy increases in areas of high tree diversity (Mitani 1985, Brockelman & Srikosamatara 1993, Nijman 2004, Fan et al 2009).…”

Sleeping site use of the white-headed langur Trachypithecus leucocephalus: The role of predation risk, territorial defense, and proximity to feeding sites

“…MCPF strategy has been reported for in platyrrhines (e.g., Ateles geoffroyi, Chapman et al, 1989; Saguinus midas, Day and Elwood, 1999;S. fuscicollis and S.mystax, Smith et al, 2007), Asian and African colobines (e.g., Trachypithecus francoisi, Zhou et al, 2009;Colobus guereza, von Hippel, 1998), and hylobatids (Hylobates pileatus, Phoonjampa et al, 2010).…”

The First Survey of the Conservation Status of Primates in Southern Burkina Faso, West Africa

“…Use of the same sleeping tree on consecutive nights may be due to the lack of predators. In high-risk environments, primates often avoid consecutive use of the same sleeping sites so as to reduce detection by predators (Li et al 2006;Phoonjampa et al 2010). The selection of sleeping trees appears to be a compromise between several factors-species, diameter and height, and location-and the preference of C. vellerosus for C. integrifolia in Kikélé may also be explained by the fact that it is also used for feeding and resting during the day, with monkeys spending up to eight hours a day on its branches.…”