SharkoFiles: Whale Shark

The whale shark, despite its name is not actually a whale, but shark, hence it is not a mammal but fish. It is regarded as the largest fish in the ocean reaching to about 40 feet in length. In spite of the large size of this shark, it is known to feed upon tiny plants and animals with their most preferred meal being the plankton. They are the gentlest monster (big shark) that can be found in the sea. They are so docile that they allow swimmers to hitch a ride on them. J

uvenile whale shark even sometimes plays with divers in the sea. Overall, the whale sharks have a lot in common with whales even though they are sharks. The whale shark unlike the Great white shark is not predatory. The whale sharks are known to be solitary creatures, although sometimes seen in groups. The social life of this species of shark still needs to be investigated.

Despite being harmless and one of the most tame sea beasts known to man, this species of shark is enlisted as a vulnerable species by IUCN simply because their population is decreasing as a result of being caught and slaughtered for food purpose, particularly in some Asian countries such as China and Pakistan.

Taxonomy

The species name of the whale shark is Rhincodon typus. It belongs to the order Orectolobiformes and family Rhincodontidae.

Morphology

The whale sharks most obvious appearance is their immense sizes. They can grow up to 40 feet long. The whale sharks have flattened head and possess a blunt snout above their mouths. In addition, similar to the catfish, they have short barbels whisker-like sensory organs protruding from their nostrils. Asides their immense appearance, this species of shark is also distinguished by the characteristic spots of unique pattern on the dorsal parts of the fish. Each whale shark has a unique spot pattern similar to the fingerprints in human. The mouth of the whale shark is around 5 feet wide having rows of more than 300 teeth. Despite having many teeth, they do not use them to feed because of their feeding style (filter feeder). They also have five large gill slits on each side of the head region, just above the pectoral fins.

Adaptation

The whale shark large mouth is well adapted for filter feeding, that is, the shark swims with its mouth open and seawater enters the mouth cavity and filter through the gill slits. The gill is made up of meshlike tissues that act like a sieve, trapping plankton and other small aquatic organisms for the shark to feed upon.

Feeding

Unlike most sharks, the whale shark do not attack and tear their prey apart. While they are carnivores and love eating meat, they are filter feeders. Their major source of food is plankton, but they also feed on shrimps, algae, as well as other marine plants. In addition, the whale shark feeds on fish eggs.

Habitat

The whale sharks are migratory animals and can be found in all tropical and warm seas across the world. They prefer to migrate to plankton rich areas. In fact, it is speculated by marine scientists that location of whale sharks can be used to estimate the presence of plankton and overall health of our oceans. They are seen in the western Atlantic Ocean from the coast of New York in United States, as well as areas including Gulf of Mexico and Caribbean Sea. The whale sharks usually stay in deep waters about 2,600 feet in depth, but sometimes swim closer to coastal areas, particularly close to the coral reef.

Reproduction

The whale shark females are known to carry a litter of more than 16 young ones at a time in their uterus. In the mid-1990s a female whale shark whose uterus contained almost 300 young was caught near Taiwan. They give birth to live young ones. Similar to many other sharks, the whale shark engage in viviparous modes of reproduction.