We investigated the mechanisms by which temperature induces seasonal reproductive behavior in red-sided garter snakes (Thamnophis sirtalis parietalis). Specifically, we addressed whether elevated temperatures during winter dormancy influence (1) diel melatonin and corticosterone rhythms; (2) sex steroid hormone and corticosterone profiles; and (3) the expression of reproductive behavior followi...

There is growing evidence from both behavioral and neurophysiological approaches that primates are able to rapidly discriminate visually between snakes and innocuous stimuli. Recent behavioral evidence suggests that primates are also able to discriminate the level of threat posed by snakes, by responding more intensely to a snake model poised to strike than to snake models in coiled or sinusoid...

Batesian mimicry, in which harmless species (mimics) deter predators by deceitfully imitating the warning signals of noxious species (models), generates striking cases of phenotypic convergence that are classic examples of evolution by natural selection. However, mimicry of venomous coral snakes has remained controversial because of unresolved conflict between the predictions of mimicry theory ...

Papuan taipans (Oxyuranus scutellatus canni), death adders (Acanthophis spp.) and Papuan blacksnakes (Pseudechis papuanus) are the most dangerous snakes along the Papuan coastline. Although the Papuan blacksnake is rare, the Papuan taipan is very common in parts of Milne Bay, Central, Gulf and Western provinces, and is the commonest venomous snake implicated in cases of snakebite. Deaths adders...

We propose a novel Active Volume Model (AVM) which deforms in a free-form manner to minimize energy. Unlike Snakes and level-set active contours which only consider curves or surfaces, the AVM is a deforming object model that has both boundary and an interior area. When applied to object segmentation and tracking, the model alternates between two basic operations: deform according to current ob...

Earthworms (Lumbricus terrestris) produce a chemical substance that is readily detected by and serves as an attractant for garter snakes (Thamnophis sirtalis). This chemoattractant is sensed by the vomeronasal system of snakes. Amino acid analysis of the chemoattractant revealed a high hydroxyproline/proline ratio and large amounts of serine and threonine. More than one-third of the residues we...

Eighteen microsatellite loci developed for a range of snake species (New World natricines, elapids, crotalids) were tested against European natricines (Natrix natrix, N. maura, and N. tessellata) in cross-species amplification experiments. Five loci were polymorphic (average expected heterozygosity 0.749 for a population of N. natrix in Amsterdam, mean sample size 47.8) and three loci were mono...

M any species that are dangerous or unpleasant to eat have evolved conspicuous signals that warn predators to avoid them. Not surprisingly, many other species that are edible to predators, from birds and butterflies to salamanders and sea slugs, have evolved to resemble these inedible species 1. By doing so, the 'mimics' receive protection from predation, just like their 'models'. This phenomen...

BACKGROUND Indigenous cultures are the result of their adaptation to the natural surroundings, in such a way that, amongst their main features is a set of knowledge, technologies and strategies for the appropriation of nature. In Cuetzalan del Progreso, Puebla, Mexico snakes represent 71.1% of the total local herpetofauna; and in addition to this, different groups of Nahuas have shown to have i...

Wild bonnet macaques (Macaca radiata) were studied in southern India to assess their ability to discriminate non-venomous, venomous and predatory snakes. Realistic snake models were presented to eight troops of bonnet macaques at feeding stations and their behavior was video-recorded 3 min before and 3 min after snake exposure. Snakes presented were: (1) venomous Indian cobra (Naja naja) displa...