Primates have been predated on by snakes throughout their evolution and as a result, antipredator responses accompanied by signs of fear are often witnessed in the wild. In captivity, however, the fear of snakes is less clear, as experiments with naïve nonhuman primates have given inconsistent results. In this study, we present evidence that naïve mouse lemurs (Microcebus murinus) and putatively naïve pig-tailed macaques (Macaca nemestrina) do exhibit fear of snakes, even though the apparent reactions are mild. In an experiment with control- or snake-odoured boxes, mouse lemurs clearly avoided feeding in the latter. When the latency of touching rubber models was measured, pig-tailed macaques took longer to touch a toy snake compared with a toy lizard. Our findings that fear of snakes is shown by naïve individuals support the hypothesis that it is innate in primates.
There is some urgency in the necessity to incorporate physiological data into mechanistic, trait-based, demographic climate change models. Physiological responses at the individual level provide the mechanistic link between environmental changes and individual performances and hence population dynamics. Here we consider the causal relationship between ambient temperature (Ta) and metabolic rate (MR), namely, the Arrhenius effect, which is directly affected by global warming through increases in average global air temperatures and the increase in the frequency and intensity of extreme climate events. We measured and collated data for several small, free-ranging tropical arboreal mammals and evaluated their vulnerability to Arrhenius effects and putative heat stress associated with climate change. Skin temperatures (Tskin) were obtained from free-ranging tarsiers (Tarsius syrichta) on Bohol Island, Philippines. Core body temperature (Tb) was obtained from the greater hedgehog tenrec (Setifer setosus) and the gray brown mouse lemur (Microcebus ravelobensis) from Ankarafantsika, Madagascar. Tskin for another mouse lemur, Microcebus griseorufus, was obtained from the literature. All four species showed evidence of hyperthermia during the daytime rest phase in the form of either Tskin or Tb that was higher than the normothermic Tb during the nighttime active phase. Potentially, tropical arboreal mammals with the lowest MRs and Tb, such as tarsiers, are the most vulnerable to sustained heat stress because their Tb is already close to Ta. Climate change may involve increases in MRs due to Arrhenius effects, especially during the rest phase or during torpor and hibernation. The most likely outcome of increased Arrhenius effects with climate change will be an increase in energy expenditure at the expense of other critical functions such as reproduction or growth and will thus affect fitness. However, we propose that these hypothetical Arrhenius costs can be, and in some species probably are, offset by the use of hyperthermic daily torpor, that is, hypometabolism at high Ta.
- MeSH
- bazální metabolismus * MeSH
- Cheirogaleidae fyziologie MeSH
- hmyzožravci fyziologie MeSH
- klimatické změny MeSH
- reakce na tepelný šok * MeSH
- strnulost * MeSH
- Tarsiidae fyziologie MeSH
- teplota MeSH
- tropické klima MeSH
- velikost těla * MeSH
- zachování přírodních zdrojů MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Filipíny MeSH
- Madagaskar MeSH
