Whale sharks live in oceans around the world, but no one knows where they breed, their migration routes, or even how many there are. Photographer Brian Skerry
The whale shark, Rhincodon typus, is a slow-moving filter feeding shark, the largest living fish species. The largest confirmed individual was 12.65 metres (41.50 ft) in length and the heaviest weighed more than 36 tonnes (79,000 lb),but unconfirmed claims report considerably larger whale sharks. This distinctively-marked fish is the only member of its genus Rhincodon and its family, Rhincodontidae (called Rhinodontes before 1984), which belongs to the subclass Elasmobranchii in the class Chondrichthyes. The shark is found in tropical and warm oceans, lives in the open sea with a lifespan of about 70 years. The species originated about 60 million years ago. Although whale sharks have very large mouths, they feed mainly, though not exclusively, on plankton, microscopic plants and animals, although the BBC program Planet Earth filmed a whale shark feeding on a school of small fish.
The species was distinguished in April 1828, following 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. He published a more detailed description in 1849. The name “whale shark” comes from the fish’s physiology; as large as a whale, it too is a filter feeder.