A lateral line system is present along the flanks. It is composed of rows of microscopic organs sensitive to water pressure changes and detects vibrations. A pair of auditory organs also detect sound waves passing through the water. Sharks reproduce sexually with internal fertilization. A pair of claspers on the pelvic fins of males transfers sperm into the female reproductive tract.
Some species are oviparous , some are ovoviviparous , and a few are viviparous .
Rays are adapted to a bottom-dwelling life style. They have dorsoventrally flattened bodies. Their jaws are used to crush mollusks and crustaceans. Enlarged pectoral fins provide propulsion for swimming. The tail in many species is whiplike and, in some, bears venomous barbs.