cooter n.

name for some types of freshwater terrapin in southern U.S., especially the common box-turtle, 1835 (first attested 1827 in phrase drunk as a cooter, but this perhaps is a colloquial form of unrelated coot), of uncertain origin, perhaps from obsolete verb coot "to copulate" (1660s), which is of unknown origin. The turtles are said to copulate for two weeks at a stretch.