Sleeping Site Selection in the Nocturnal Northern Lesser Galago (Galago senegalensis) Supports Antipredator and Thermoregulatory Hypotheses

Abstract

Sleep is an important and time-consuming activity, during which animals may be particularly vulnerable. Selecting a suitable sleeping site is therefore essential for an individual's fitness. Here we test the importance of antipredator and thermoregulatory hypotheses for the sleeping site preference of a nocturnal primate, the Northern lesser galago (Galago senegalensis), in Northern Tanzania. During June to August of 2015 and 2016 we conducted daily surveys of sleeping sites to record the number of galagos and their location within the sleeping tree, and used focal follows to record when galagos reached and left sleeping sites. We collected vegetation data for sleeping sites (N = 47) and matched controls, and placed data loggers in sleeping (N = 14) and control locations to compare temperature and humidity. Sleeping group sizes were similar to that of G. senegalensis in The Gambia, and the mean proportion of visits in which galagos were present at each site was 27 ± SD 25%. Galagos slept on branches (N = 29), nests (N = 6), palm leaves (N = 6), and in tree cavities (N = 1). Palm leaves have not been previously recorded as regular sleeping sites for galagos and were overrepresented relative to their occurrence in the habitat. Random forest classification analysis revealed that galagos sleep in areas with greater canopy cover and connectivity, greater mid-Extended author information available on the last page of the article level vegetation cover, higher tree density, and a greater number of Acacia trees. Sleeping locations had significantly lower mean temperatures but greater mean humidity than control locations. Our findings support predator avoidance and thermoregulation as drivers of nesting behavior. In particular, the characteristics of galago sleeping sites correspond well to those expected for protection from aerial predators, while those related to protection from terrestrial predators seem to play a minor role.

Behavioral adjustments and support use of François' langur in limestone habitat in Fusui, China: Implications for behavioral thermoregulation

“…For example, Sapajus cay in eastern Paraguay prefer larger trees with a wider crown, which is thought to be related to thermoregulation (Smith, Hayes, Smith, & Dickens, 2018). Additionally, sleeping sites are also selectively used by primates to avoid thermal stress (Ellison et al, 2019; Karanewsky & Wright, 2015). In our study, T. francoisi spent most of their time staying on branches (including rock shelter by trees and ledges) when daily T a was highest (Table 2).…”

Predator avoidance and food patch proximity influence sleeping site use of Assamese macaques in a limestone forest of Southwest Guangxi, China

“…Primates have evolved an array of strategies to reduce predation risk when sleeping (Anderson, 1984(Anderson, , 1998. The predator avoidance hypothesis states that primates should select sleeping sites with physical characteristics that reduce their detection and chance of access by predators and/or facilitate escape (Anderson, 1998(Anderson, , 2000Ellison et al, 2019).…”

“…Primates have evolved an array of strategies to reduce predation risk when sleeping (Anderson, 1984, 1998). The predator avoidance hypothesis states that primates should select sleeping sites with physical characteristics that reduce their detection and chance of access by predators and/or facilitate escape (Anderson, 1998, 2000; Ellison et al, 2019). For example, northern pig‐tailed macaques ( Macaca leonina ) select sleeping sites in trees with higher canopies and more stems, which potentially reduce their detection by predators and make access for predators more difficult (Gazagne et al, 2020).…”

Sex and age differences in tree cavity dependence in a small arboreal marsupial

“…Shelter sites are critical for animal survival because they provide protection from the weather and from predators (Di Bitteti et al, 2000;Ellison et al, 2019). They may also be needed specifically to protect offspring as they grow and develop (e.g., Soderquist, 1993).…”