Whale Shark - Rhincodon typus

Physical attributes of the whale shark

A large, plankton-eating shark, Rhincodon typus,or the whale shark, is found in all tropical seas of the world. The largest known specimens are 50 ft (15 m) long, making them the largest fish in the world. The whale shark feeds largely on plankton, as well as on small fish and crustaceans. It is the only large shark with its mouth at the front of its head rather than on the underside. The whale shark's body is stout but streamlined, like that of a whale. It is dark brown above, with many white or yellow spots, and white or yellow below. The whale shark is a docile, torpid fish; it does not attack, even on provocation, but has been known to collide with boats. It is classified in the phylum Chordata , subphylum Vertebrata, class Chondrichthyes, order Selachii, family Rhincodontidae.

Family Rhincodontidae (whale shark)The largest of modern fishlike lower vertebrates. One species only (Rhincodon typus); is found in open waters of all oceans, mostly in tropics, but north to 42 N latitude (near New York) and south to 3355' S (Table Bay, South Africa). It is generally Sluggish and inoffensive.

Eating habits

The whale shark (Rhincodon typus) and basking shark (Cetorhinus maximus), resemble the baleen whales in feeding mode as well as in size. They feed exclusively or chiefly on minute passively drifting organisms (plankton). To remove these from the water and concentrate them, each of these species is equipped with a special straining apparatus analogous to baleen in whales. The basking shark has modified gill rakers, the whale shark elaborate spongy tissue supported by the gill arches. The whale shark also eats small, schooling fishes.

Reproduction

In oviparous (egg-laying) species, such as the whale shark, the eggs are enveloped in a horny shell. Usually equipped with tendrils for coiling around solid objects or with spikelike projections for anchoring in mud or sand. The egg cases of most species are more or less pillow-shaped.

An egg of a whale shark found in the Gulf of Mexico measured 30 centimetres (12 inches) long by about 14 centimetres (51/2 inches) wide and was eight centimetres (three inches) thick. Protected by the shell and nourished by the abundant yolk, the embryo of an oviparous species develops for 4 1/2 to 14 3/4 months before hatching.