Hunter–gatherers and other primates as prey, predators, and competitors of snakes

Abstract

Relationships between primates and snakes are of widespread interest from anthropological, psychological, and evolutionary perspectives, but surprisingly, little is known about the dangers that serpents have posed to people with prehistoric lifestyles and nonhuman primates. Here, we report ethnographic observations of 120 Philippine Agta Negritos when they were still preliterate hunter–gatherers, among whom 26% of adult males had survived predation attempts by reticulated pythons. Six fatal attacks occurred between 1934 and 1973. Agta ate pythons as well as deer, wild pigs, and monkeys, which are also eaten by pythons, and therefore, the two species were reciprocally prey, predators, and potential competitors. Natural history data document snake predation on tree shrews and 26 species of nonhuman primates as well as many species of primates approaching, mobbing, killing, and sometimes eating snakes. These findings, interpreted within the context of snake and primate phylogenies, corroborate the hypothesis that complex ecological interactions have long characterized our shared evolutionary history.

Pulvinar neurons reveal neurobiological evidence of past selection for rapid detection of snakes

“…However, because the degree of facial expression in primates varies by body size, phylogenetic history, and group size (as a proxy for sociality) (38,39), detecting threat from facial expression alone may not be universal among primates. In contrast, since the origin of primates, snakes have been a universal threat; both primates and snakes that can kill them (i.e., constrictors and venomous snakes) have their greatest diversity in tropical ecosystems (1,2,40,41). Our data provide unique neuronal evidence supporting the hypothesis that snakes provided a novel selective pressure that contributed to the evolution of the primate order by way of visual modification (2,5).…”

“…As is the case with snakes, being able to quickly detect and evade an angry conspecific undoubtedly has substantial survival value (1,37). However, because the degree of facial expression in primates varies by body size, phylogenetic history, and group size (as a proxy for sociality) (38,39), detecting threat from facial expression alone may not be universal among primates.…”

“…As the only natural objects with those characteristics, snakes may have been among the first models used in representational imagery created by modern humans. Our interest in snakes may have originated much further back in time; our primate lineage has had a long and complex evolutionary history with snakes as competitors, predators, and prey (1). The position of primates as prey of snakes has, in fact, been argued to have constituted strong selection favoring the evolution of the ability to detect snakes quickly as a means of avoiding them, beginning with the earliest primates (2,5).…”

“…The attributes of snakes and our relationships with them have been topics of discussion in fields as disparate as religion, philosophy, anthropology, psychology, primatology, and herpetology (1,2). Ochre and eggshells dated to as early as 75,000 y ago and found with cross-hatched and ladder-shaped lines (3,4) resemble the dorsal and ventral scale patterns of snakes.…”

Mount Pinatubo, Inflammatory Cytokines, and the Immunological Ecology of Aeta Hunter-Gatherers

“…Tropical rainforests can be challenging environments for hunter-gatherers; parasitic and infectious disease species abound at low latitudes (Guernier et al 2004), and the risk of predation is high for some populations (Headland and Greene 2011). As a result, tropical hunter-gatherers often endure relatively high rates of agespecific mortality (Hill et al 2007).…”