 Most lizards have toes ending in stout claws, forming from the last scale on the toe.In snakes, feet and claws are absent, but in many boids such as "Boa constrictor", remnants of highly reduced hind-limbs emerge with a single claw as "spurs" on each side of the anal opening.Lizard claws are used as aids in climbing, and in holding down prey in carnivorous species.