Ironically, while the smaller sharks stick to the previously described diet, the largest kinds, such as the whale shark and the basking shark, eat plankton and tiny plants. Food is stored in a J-shaped stomach, and though the chondrichtyes' intestines are short, they acheive increased surface area through use of a spiral valve. The digestive tracts of chondrichthyes has a separate mouth and anus. The size of chondrichtyes' bodies can range from 45 feet to merely 9 inches, as exemplified by the whale shark and the cookie-cutter shark, respectively. A whale shark.
Rays have broad, flat bodies, with eyes on their upper surface and a mouth and gil slits underneath.
This is useful both in stalking prey and in hiding from predators. Skates are more markedly flat-bodied rays. A site on the male's pelvic fins transfers sperm into the reproductive tract of the female, and the females internally fertilize their eggs. Sharks have highly diverse reproductive patterns, and may produce young in one of three ways, Oviparous chondrichthyes lay eggs which hatch externally. Ovoviviparous chondrichthyes have eggs which develop in the oviducts of the female and hatch in the uterus before birth.