Social organisation of the northern giant mouse lemur Mirza zaza in Sahamalaza, north western Madagascar, inferred from nest group composition and genetic relatedness

Abstract

Shelters such as leaf nests, tree holes or vegetation tangles play a crucial role in the life of many nocturnal mammals. While information about characteristics and availability of these resources may help in conservation planning, nest use gives an indication about a species’ social organisation. The northern giant mouse lemur (Mirza zaza) is threatened by habitat loss within its restricted range. Our aim was to examine nest site preferences of M. zaza and to explore the species’ social organisation by examining sleeping site aggregation size and genetic relatedness within and between such aggregations. In the Ankarafa Forest inside Sahamalaza – Iles Radama National Park, northwestern Madagascar, we radio-tagged five male and three female M. zaza and followed them for 2.5 months during the dry season. We identified sleeping trees and observed animals during emergence in the evening and return in the morning. We compared sleeping trees and microhabitats around nest sites to trees and habitat used during nightly activity and to random sites. We found that nests were well covered by canopy, even during the dry season, and were located near the tree trunk a few meters below the tree top. Nest sites were characterised by large (> 30 cm DBH) and tall trees (>16 m) with many lianas. Up to four animals shared one to three group-exclusive nests for up to 50 days. Two of the nest groups included two and three males with fully developed testes. Relatedness data revealed that the adult males sharing nests were either unrelated or closely related. These data suggest that M. zaza is sleeping in social nest groups including multiple males, which is unusual among nocturnal strepsirrhines. Apart from protecting suitable sleeping trees and discouraging selective logging of large trees, we recommend conducting further studies on the species’ social organisation throughout an entire season.

Social relationships among captive male pygmy slow lorises (Nycticebus pygmaeus): Is forming male same‐sex pairs a feasible management strategy?

“…One pair showed similar levels of social behaviors between the two observation periods, another pair increased the amount of affiliative behaviors and one pair decreased the amount of affiliative behaviors and increased aggressive behaviors ( sharing is often observed in various wild, nocturnal strepsirrhines (Bearder et al, 2003;Nekaris & Bearder, 2007;Rode et al, 2013), as researchers often analyze grouping tendencies by observing daytime sleep sites in the wild (Bearder et al, 2003). Although it is rare for multiple males to share sleep sites, it has been reported in the slender loris and in giant mouse lemurs (Nekaris, 2003;Rode et al, 2013). This result is not consistent with those observed in the solitary sleeping patterns of wild pygmy slow lorises (Starr & Nekaris, 2020).…”

The effects of body size, activity, and phylogeny on primate sleeping ecology

“…In contrast to nocturnal species, diurnal primates are more likely to spend the night using cliffs or tall trees as sleeping sites. Multiple microhabitat features offer antipredator benefits and are known to influence primate sleeping site selection, including tree height (Albert et al, 2011; Di Bitetti et al, 2000; Rode et al, 2013) density of undergrowth (Dagosto et al, 2001) and canopy cover (Hankerson et al, 2007; Rode et al, 2013). For instance, elevated locations can increase safety during the night since many large predators tend to live on the ground and they offer a vantage point from which to spot terrestrial predators (Bidner et al, 2018; Hamilton III, 1982).…”

Effects of forest fragmentation on the dietary ecology and activity of a nocturnal lemur community in North West Madagascar

“…SIRNP is a 26,000 ha protected area located between the latitudes of 14°04′S ‐ 14°37′S and the longitudes of 47°52′E ‐ 48°04′E in Madagascar's Sofia Region (Volampeno et al, 2011) (Figure 1). In addition to its designation as a National Park, SIRNP is also classed as a United Nations Educational, Scientific and Cultural Organization Biosphere Reserve (Rode et al, 2013) and, despite its protected status, it has undergone heavy habitat destruction and fragmentation in recent years (Seiler et al, 2014). Although some isolated forests and matrices of gallery and scrub vegetation remain within the National Park, large areas of SIRNP are now characterized by anthropogenic savannah and grasslands (Volampeno et al, 2011).…”