WHY SNAKES HAVE FORKED TONGUES

The serpent's forked tongue has intrigued humankind for millennia, but its function has remained obscure. Theory, anatomy, neural circuitry, function, and behavior now support a hypothesis of the forked tongue as a chemosensory edge detector used to follow pheromone trails of pre y and conspecifics. The ability to sample simultaneously two points al ong a chemical g rad lent provides the basis for instantaneous assessm ent of trail location. Forked tongues have evolved at least twice, pos sibly four times, among squamate reptiles, and at higher taxonomic lev els, forked tongues are always associated with a wide searching mode o f foraging. The evolutionary success of advanced snakes might be due, in part, to perfection of this mechanism and its role in reproduction.