The Peerless Squid
Say what? You bet. Efficient and elegant predators, the class Cephalopoda (the taxonomic subdivision to which squid belong) boasts the largest invertebrate on record -- although not big or bad enough to consume submarines or other Hollywood offerings. The giant squid, some argue, "stands at the apex of invertebrate evolution," and possesses the most highly developed nervous system in the invertebrate world. Some species are easily raised and handled and therefore are used extensively in biomedical research. These tentacled wonders have provided some critical insights into our understanding of the complex system of nerves and nerve centers in animals, findings that have helped scientists grasp the finer points of the human central nervous system.

Photo by R.T. Hanlon. Courtesy of the National Resource Center for Cephalopods.