The whale shark, Rhincodon typus, is a slow-moving filter feeding shark and the largest extant fish species. The largest confirmed individual had a length of 12.65 meters (41.50 ft) and a weight of more than 21.5 metric tons (47,000 lb), and there are unconfirmed reports of considerably larger whale sharks. Claims of individuals over 14 meters (46 ft) long and weighing at least 30 metric tons (66,000 lb) are not uncommon. The whale shark holds many records for sheer size in the animal kingdom, most notably being by far the largest living non-mammalian vertebrate, rivaling many of the largest dinosaurs in weight. It is the sole member of the genus Rhincodon and the family, Rhincodontidae (called Rhiniodon and Rhinodontidae before 1984), which belongs to the subclass Elasmobranchii in the class Chondrichthyes. The species originated approximately 60 million years ago.
The whale shark is found in tropical and warm oceans and lives in the open sea with a lifespan of about 70 years. Although whale sharks have very large mouths, as filter feeders they feed mainly, though not exclusively, on plankton, which are microscopic plants and animals. However, the BBC program Planet Earth filmed a whale shark feeding on a school of small fish. The same documentary showed footage of a whale shark timing its arrival to coincide with the mass spawning of fish shoals and feeding on the resultant clouds of eggs and sperm.
The species was distinguished in April 1828 after the harpooning of a 4.6 metres (15.1 ft) specimen in Table Bay, South Africa. Andrew Smith, a military doctor associated with British troops stationed in Cape Town, described it the following year.[The name "whale shark" comes from the fish's physiology, being as large as some species of whales and also a filter feeder like many whale species. from WIKIPEDIA