Infant nest and stash sites of variegated lemurs (Varecia rubra): The extended phenotype

Very few primate species give birth to litters and build nests in which to care for them. Those that do are small-bodied, nocturnal, and solitary. Variegated lemurs are exceptional in that they bear litters in arboreal nests, yet are relatively large-bodied, day-active, and gregarious. Furthermore, they raise their young cooperatively and practice absentee parenting; non-clinging young are transported orally and periodically stashed in arboreal spots that are supportive, sheltered, and usually concealed. Following birth, infant nest and stash trees were mapped, measured, and taxonomically identified in a population of red variegated lemurs in Masoala National Park. About 40 trees were used per litter for nesting and stashing young in adjacent, non-overlapping core areas within the community. These were the largest trees in the forest, even larger than those used for feeding. Furthermore, most occur in valleys and are laced with lianas, creating sites that buffer young from predation, accidental falls, and to some degree, thermal stress. In combination, the number of nest and stash trees used per litter, their characteristics, and their geo-spatial arrangement indicate that such sites are both select and limited in the landscape, exposing the dependence of red variegated lemurs on intact forest canopies for raising non-clinging young within the context of an absentee parenting system. Nest and stash sites are in effect Varecia's extended phenotype. Logging of large trees in Madagascar's eastern rain forests is considered a major factor resulting in local extinctions of variegated lemurs because they rely heavily upon large, mature trees for fruit. However, this study suggests that removal of large trees may more directly precipitate local extinctions by impeding their ability to reproduce. Long-term survival of red variegated lemurs will depend upon efforts to end harmful timber extraction in its remaining stronghold, the Masoala Peninsula.