'Anal spurs' are the
vestigial remnants of legs found on each side of the
vent in primitive
snakes, such as
boas and
pythons. The
bone is considered a
hip bone, which has no connection with the spine and simply "floats" in the muscle mass. There is sometimes a bone, considered a
femur, which sticks out of the snake's side. This primitive femur is then covered by a
corneal spur, which resembles a
claw. Males' spurs are generally longer and more pointed than females', and are used for clasping and tickling during
courtship and
mating. Sometimes they are used during fights to scratch the opponent.