Fear reactions to snakes in na⟨ve mouse lemurs and pig-tailed macaques

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 na < ve nonhuman primates have given inconsistent results. In this study, we present evidence that na < ve mouse lemurs (Microcebus murinus) and putatively na < ve 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 na < ve individuals support the hypothesis that it is innate in primates.