California Sea Hare

The California sea hare, Aplysia californica, is a species of sea slug in the sea hare family, Aplysiidae, found along the coast of California and northwestern Mexico, including the Gulf of California, typically in waters no deeper than 18 to 20 meters. It can reach up to 75 centimeters when fully extended and up to 7 kilograms in weight, with coloration ranging from pale gray to greenish or reddish-brown depending on diet, an internal shell, and four sensory tentacles. Its relatively simple nervous system of about 20,000 large, easily identified neurons has made it a major laboratory model for studying learning and memory, most notably in the work of Nobel laureate Eric Kandel.