Snakes are elongated, limbless reptiles in the suborder Serpentes. They are ectothermic vertebrates covered in overlapping scales. Many species have skulls with multiple joints, allowing them to swallow prey much larger than their heads, a feature known as cranial kinesis. Their paired organs, like kidneys, are arranged one in front of the other due to their narrow bodies, and most have only one functional lung. Some species also have a pelvic girdle with vestigial claws beside the cloaca.
