Whale Shark (Rhincodon typus)

 

Class: Elasmobranchii
Order: Orectolobiformes
Family:    Rhincodontidae
Size:    Length: 18 to 50 feet (5.5 to 15 m)
Weight: Up to 27,000 pounds (12,500 kg)
Diet: Plankton, sardines, anchovies and krill
Distribution: Temperate and subtropical oceans worldwide
Young:  Several hundred pups during one pregnancy
Animal Predators:  Unknown
IUCN Status: Vulnerable
Terms: Young: Pups
Lifespan: Up to 100 years or more in the wild

 

Facts/Trivia:

·         Scuba divers used to hitch a ride on these gentle giants by grabbing onto a fin, but now this action is frowned on as it may upset or even harm the shark

·         One whale shark is approximately as heavy as two elephants and as long as five family cars or two school buses.

·         In Taiwan, a pregnant whale shark was found to contain about 300 embryos in her uteri.

 

Description

Whale sharks are the biggest sharks and fish in the world, and despite their name, they are not whales. They have a broad head and a wide mouth that can be up to four feet (1.2 m) wide. They have a rounded snout, small eyes, large fins, and a spiracle (a gill used for breathing when the shark is resting on the sea floor), located just behind the eye. The top fin on the tail is much larger than the lower fin. Whale sharks have uniquely beautiful patterns on their skin, with shades of blue, dark grey, bronze or greenish-grey on the upper side of the body and a cream colour on the underside. The random white dots and lines along their backs are distinguishing features, and their patterns have helped scientists identify individuals during research. 

 

Habitat

Whale sharks prefer to live in warm water, ranging about 70° F (21° C). They are found in both tropical and subtropical oceans worldwide.

 

Feeding Habits

Whale sharks are filter feeders that feed on tiny zooplankton and small fish, such as sardines and anchovies, that they strains through sieve-like gills. They also eat small, shrimp-like creatures called krill. They swim along with their mouth open and when they find plankton or a school of small fish, they swing their head from side to side to suck in as many creatures as they can. After closing their mouth, whale sharks use gill rakers that filter the nourishment from the water. Whatever does not pass back out through the gills is eaten. Gill rakers are bristly structures in the shark’s mouth that trap the small organisms that the shark then swallows. 

 

Reproduction

Whale sharks are viviparous (meaning the young hatch from eggs inside the mother’s body and are born later after they leave the uteri), giving birth to live young. Pregnant females give birth to hundreds of pups during one pregnancy. Newborn whale shark pups measure approximately two feet (61 cm) in length. Whale sharks reach maturity at between 25 and 30 years of age.

 

Behaviour

Whale sharks are solitary, benign giants, with calm demeanors. They pose no threat of attack and are non-aggressive towards divers. They are slow swimmers, averaging a speed of about three miles (5 km) per hour. 

 

Conservation

Whale sharks are still caught for food through much of their territory, and their numbers have been declining. However, several countries, including the United States, Australia, India and the Philippines, have banned whale shark hunting within their waters.

 

Sources

http://animaldiversity.ummz.umich.edu/accounts/rhincodon/r._typus$narrative.html

http://www.whaleshark.org/biology.html

http://www.enchantedlearning.com/subjects/sharks/species/Whaleshark.shtml

http://www.panda.org/resources/publications/species/underthreat/page28.htm

Giant Shark, Megalodon, Prehistoric Super Predator, Caroline Arnold, (p.28)
The Truth About Great White Sharks, Mary M. Cerullo, (p.8)
Totally Amazing Sea Creatures, Golden Books Publishing (p. 31)
Sharks! Strange and Wonderful, Laurence Pringle (p. 13)
A Sea of Sharks From A To Z, Sharkabet, Ray Troll, Published in association with the American Museum of Natural History (p. 39)
The Darling Kindersly Picturepedia, Sea Life (p.24)
The Living Sea, Orbis Publishing, Robert Burton, Carole Devaney and Tony Long (p. 67-69)
Creatures of the Deep, In Search of the Sea’s “Monsters” and the world they live in, Erich Hoyt (p. 18, 90, 93-94)
Sharks, Lee Server (p.21)
The Encyclopedia of Sharks, Steve and Jane Parker (p. 64, 186)
Sharks, A Portrait of the Animal World, Andrew Cleave (p. 14)