Sleeping site preferences in tufted capuchin monkeys (Cebus apella nigritus)

Abstract

The characteristics and availability of the sleeping sites used by a group of 27 tufted capuchin monkeys (Cebus apella nigritus) were studied during 17 months at the Iguazu National Park, Argentina. We tested different hypotheses regarding possible ultimate causes of sleeping-site selection. Most sleeping sites were located in areas of tall, mature forest. Of the 34 sleeping sites the monkeys used during 203 nights, five were more frequently used than the others (more than 20 times each, constituting 67% of the nights). Four species of tree (Peltophorum dubium, Parapiptadenia rigida, Copaifera langsdorfii and Cordia trichotoma) were the most frequently used. They constituted 82% of all the trees used, though they represent only 12% of the trees within the monkeys' home range which had a diameter at breast height (DBH) > 48.16 cm (1 SD below the mean DBH of sleeping trees). The sleeping trees share a set of characteristics not found in other trees: they are tall emergent (mean height +/- SD = 31.1+/-5.2 m) with large DBH (78.5+/-30.3 cm), they have large crown diameter (14+/-5.5 m), and they have many horizontal branches and forks. Adult females usually slept with their kin and infants, while peripheral adult males sometimes slept alone in nearby trees. We reject parasite avoidance as an adaptive explanation for the pattern of sleeping site use. Our results and those from other studies suggest that predation avoidance is a predominant factor driving sleeping site preferences. The patterns of aggregation at night and the preference for trees with low probability of shedding branches suggest that social preferences and safety from falling during windy nights may also affect sleeping tree selection. The importance of other factors, such as seeking comfort and maintaining group cohesion, was not supported by our results. Other capuchin populations show different sleeping habits which can be explained by differences in forest structure and by demographic differences.

The cost of defeat: Capuchin groups travel further, faster and later after losing conflicts with neighbors

“…Contrary to my prediction, in fact, groups were significantly less likely to re‐use their sleeping site after losing an intergroup conflict. Whether this tendency to change sleeping sites exposes them additional costs, such as increased predation risk (Di Bitetti et al, ; Holmes et al, ), has yet to be explored. However, the patterns of space use documented in this study are consistent with the hypothesis that defeat forces groups to forfeit access to their preferred (i.e., first choice) foraging locations and move to other, presumably lower quality, parts of their range.…”

Sleeping site and tree selection by Sichuan snub‐nosed monkeys (Rhinopithecus roxellana) in Baihe Nature Reserve, Sichuan, China

“…On a smaller spatial scale, the characteristics of sleeping trees are also important, particularly for arboreal primate species (von Hippel, ; Hankerson, Franklin, & Dietz, ). They have been shown to select different characteristics of sleeping trees to (1) make access more difficult for terrestrial predators, that is, tall emergent trees (Bitetti, Vidal, Baldovino, & Benesovsky, ; Cui, Tai, Lin, & Wen, ), higher first branches (Liu & Zhao, ; Li et al, ), and crowns without lianas (Barnett, Shaw, Spironello, MacLarnon, & Ross, ; Fei et al, ; Phoonjampa, Koenig, Borries, Gale, & Savini, ); (2) enhance their field of view to better monitor the surrounding environment, that is, less shrub cover (Hankerson et al, ), close proximity to riverbanks (Bernard, Matsuda, Hanya, & Ahmad, ; Thiry et al, ); (3) provide escape routes by utilizing arboreal connectivity between surrounding trees (Bernard et al, ; Fan & Jiang, ; Hankerson et al, ); (4) shelter from extreme climatic conditions in both tropical and temperate habitats, that is, utilizing dense canopies (Cui et al, ; Xiang, Nie, Chang, Wei, & Ming, ); palm trees and tree hollows (Heymann, ). Sleeping site and tree selection can also be influenced by other factors, for example, group size (Anderson, ; Bitetti et al, ) and to minimize parasitic infections (Feilen & Marshall, ).…”

Nocturnal sleeping habits of the Yunnan snub‐nosed monkey in Xiangguqing, China

“…For example, François' Langurs ( Trachypithecus françoisi ) entered sleeping sites earlier in winter and spring than in summer and autumn in response to seasonal changes in photoperiod [Zhou et al, 2009]. In addition to climatic factors, predator avoidance is likely a major influence [Anderson, 1998; Di Bitetti et al, 2000; Zhang, 1995]. Animals' behavior should minimize their vulnerability to predation [Anderson, 1984; Reichard, 1998].…”