Why snakes have forked tongues.

Sexual size dimorphism of the tongue in a North American pitviper

Sexual dimorphisms – phenotypic dissimilarities between the sexes – are common and widespread among plants and animals, and classical examples include differences in body size, colour, shape, ornamentation and behaviour. In general, sexual dimorphisms are hypothesized to evolve by way of sexual selection acting on one sex through priority-of-access for sexual partners via mate choice and/or int...

The mechanism of chemical delivery to the vomeronasal organs in squamate reptiles: a comparative morphological approach.

Vomeronasal chemoreception, an important chemical sense in squamate reptiles (lizards and snakes), is mediated by paired vomeronasal organs (VNOs), which are only accessible via ducts opening through the palate anteriorly. We comparatively examined the morphology of the oral cavity in lizards with unforked tongues to elucidate the mechanism of stage I delivery (transport of chemical-laden fluid...

The forked tongue and edge detection in snakes (Crotalus oreganus): an experimental test.

Many stimulus-detection systems are lateralized to allow for simultaneous comparison of paired stimuli. It has been hypothesized that the deeply forked tongue of snakes and some derived lizards functions as a chemical edge detector where cues gathered by each tine are kept separate to provide two points of lateral odor assessment by the central nervous system via vomeronasal input. While follow...

Forked Tongues Revisited: Molecular Apomorphies Support Morphological Hypotheses of Squamate Evolution

How the snake lost its legs

mystery of how the snake lost its legs might make a good 'Just so' story but it's also a tantalizing developmental question. Snakes have hundreds of similar vertebrae, as shown by the stained skeleton of a python embryo, Antaresia maculosa, (24 days after egg-laying) at top left. Snakes have no forelimbs but pythons have a pair of hindlimb rudiments (removed in picture at top right) at the junc...