Anal spurs on a male, albino burmese python

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.

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