Whale Shark

The whale shark whose scientific name is RHINCODON TYPUS, lives up to 80-150 years and ranges a length from 9m to 12m, weighs 12.5 tons. The largest confirmed individual was 18.8 m (61.7 feet) long.
This species reaches its maturity around 20-30 years.
 

Their growth slows as they cease to be young, for when young they show a quick growth rate.
Female whale sharks are polygamous (they have several sexual partners) and ovoviviparous (eggs are hatched and hatch inside the mother’s body). They reach sexual maturity at around 30 years of age and give birth to fully formed live young that show between 40 and 60 cm long.
 

The embryos feed on egg yolk sacs, while they are inside the mother’s uterus. Not all pups are born at the same time, so the researchers assume that the female retains sperm and releases the offspring in a steady stream over a period. Experts suggest that the male stores the spermatozoon, being able to fertilize eggs in successive stages, which allows one male to fertilize the entire clutch, so that the female could mate with only one whale shark.
 

The shark has a streamlined body, cylindrical in shape, wider in the middle area and accentuated at both ends, tail and head. Its skeleton is made of thick and flexible cartilage. The head of whale sharks is flattened and wide. They have a snout. Their mouth is large and can measure about 1.5 meters wide;
and in each jaw has between 300 and 350 teeth.
 

The whale shark is not a large predator of the oceans, although it is gigantic. It feeds on small organisms such as small crustaceans, plankton, some fish and molluscs, such as squid. Whale sharks spend nearly eight hours a day swallowing about 10,000 barrels of ocean water.
Suction and filtration are their feeding strategies. So, these sharks swim around with their mouth open, “suck in” their prey by pumping through their gills (technique: “cross-flow filtration”). After this process, the whale shark closes its mouth, thus retaining the plankton in its filtering organs, expelling the excess water through its gills.
 

The whale shark is distributed throughout the great oceans, inhabiting tropical and temperate regions, with the exception of the Mediterranean Sea. They prefer to dwell in warmer waters, shallow waters of 100m deep and in reefs, and can migrate thousands of kilometres to different feeding grounds, but only at a slow swimming speed of about 3 miles per hour.
These sharks are located between latitudes 30th N and 35th S, sometimes they can be found up as far north as 41 st N and 36.5 th S.
 

Adult whale sharks have no known natural predators, although sometimes blue marlins and blue sharks attack small individuals.

The most significant threat to this species is humans, as the whale shark is fished for commercialization of some of its body parts. For example: its meat is used to make dried, fresh, or salted dishes; its fins are used to make shark fin soup; its liver is used to make oil; its organic remains are used in the production of fish meal; its cartilage is used in natural medicines; and the skin is used in the leather industry.

 

Besides fishing, the other conditioning factor for the extinction of this species is collision with ships and the fact that these fish can´t rise to the surface to feed due to the ecological damage caused by the oil slick.
Whale sharks are not aggressive and don´t threaten humans, which is why they are called “Gentle giants”. They may, out of curiosity, approach and examine people in the water, but they allow divers to hang onto their dorsal fins for a stroll, or even the researchers and divers to swim right next to them.
The biggest risk they pose to humans is to accidentally hit someone with their fin if they swim too close.
On the other hand, the whale shark spends a lot of time in surface waters and is, therefore, exposed to high levels of ultraviolet rays.

​