title: Hibernation in the pygmy slow loris (Nycticebus pygmaeus): multiday torpor in primates is not restricted to Madagascar.
abstract: Hibernation and short daily torpor are states of energy conservation with reduced metabolism and body temperature. Both hibernation, also called multiday torpor, and daily torpor are common among mammals and occur in at least 11 orders. Within the primates, there is a peculiar situation, because to date torpor has been almost exclusively reported for Malagasy lemurs. The single exception is the African lesser bushbaby, which is capable of daily torpor, but uses it only under extremely adverse conditions. For true hibernation, the geographical restriction was absolute. No primate outside of Madagascar was previously known to hibernate. Since hibernation is commonly viewed as an ancient, plesiomorphic trait, theoretically this could mean that hibernation as an overwintering strategy was lost in all other primates in mainland Africa, Asia, and the Americas. However, we hypothesized that a good candidate species for the use of hibernation, outside of Madagascar should be the pygmy slow loris (Nycticebus pygmaeus), a small primate inhabiting tropical forests. Here, we show that pygmy slow lorises exposed to natural climatic conditions in northern Vietnam during winter indeed undergo torpor lasting up to 63 h, that is, hibernation. Thus, hibernation has been retained in at least one primate outside of Madagascar.
authors.affiliation: Department of Integrative Biology and Evolution, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ruf
authors.affiliation: Endangered Primate Rescue Center, Cúc Phương, Ninh Bình, Vietnam.|1185 East 39th Place, Eugene, Oregon, USA.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Streicher
authors.affiliation: Department of Integrative Biology and Evolution, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria.
authors.forename: Gabrielle L
authors.initials: GL
authors.lastname: Stalder
authors.affiliation: Endangered Primate Rescue Center, Cúc Phương, Ninh Bình, Vietnam.
authors.forename: Tilo
authors.initials: T
authors.lastname: Nadler
authors.affiliation: Department of Integrative Biology and Evolution, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria.
authors.forename: Chris
authors.initials: C
authors.lastname: Walzer
mesh_terms: D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology*; D006605:Hibernation / Q000502:physiology*; D007900:Lemur / Q000502:physiology; D008142:Lorisidae / Q000378:metabolism / Q000502:physiology*; D008270:Madagascar; D012621:Seasons; D064348:Torpor / Q000502:physiology