Whale Sharks (Rhincodon typus) are the largest shark species, and the largest of any fish species alive today. Each shark has a unique pattern of spots (like a fingerprint) that can be used to identify individuals.
They are gentle giants, and a favorite of many snorkelers and divers, who enjoy swimming with the Whale Sharks as they are feeding on the surface.
Description
Whale Sharks are very large, reaching sizes up to 20m (that’s over 65 feet!) and weighing an average of 15 TONS. They have a very distinct coloration/pattern with light stripes and dots along their back and fins.
Image courtesy of WWF
- They have a broad, flat head with more than 300 rows of very small, pointed teeth.
- Their mouth can reach up to 4 feet across.
- The inside of their mouth contains velums (specialized flaps that prevent backflow of water and loss of food).
- They have a specialized filter used for filter feeding.
- Their skin is very thick (up to 4 inches) and rubbery, protecting it from many predators.
Diet
Despite whale shark’s large size, they feed selectively on plankton, traveling large distances with plankton migrations in the search for food.
Image courtesy of Matthew Gush
The are one of three filter feeding sharks, among megamouth and basking sharks, that have a specialized filtration system used to catch and digest prey. They will swim with their mouth open, filtering seawater through their gill slits while a mesh-like tissue in the internal gill catches plankton, zooplankton, and other small organisms
They generally look for food at the surface of the water and have been seen with their tails pointed downward and mouth towards the surface, bobbing up and down in the water to catch prey. This is called ventricle suction feeding.
Image courtesy of Nature Tripper
Though their main diet consists of small marine organisms, they will also eat small fish and mollusks, including sardines, anchovies, and squid.
Habitat
Whale Sharks are found in tropical waters throughout the world. They are usually found between 30 North and 35 South in the Atlantic, Pacific, and Indian Oceans. They are a migratory species, covering long distances at a time in search of food and possibly for breeding.
Image courtesy of Seethewild
Reproduction
Its thought that Whale Sharks sexually mature when males are around 17 and females are 19-22 years old. They are ovoviparous and give birth to live pups, with reports of up to 300 in one litter. Newborns typically measure 21 to 25 inches long. When small they are vulnerable to many predators including other sharks, and even blue marlin.
The lifespan of a Whale Shark ranges from 60 to 100 years.
Threats
Whale Sharks are listed as Endangered on the IUCN Red List. Added to the list in 2016, their populations have seen drastic declines. With their large size they get entangled in fishing net and trawls, and are unable to get themselves out. They are also subject to bycatch, boat strikes, ingesting marine debris and micro plastics, and their large fins have been found in shark finning markets to be made into shark fin soup.
Image courtesy of IUCN Red List
Ecotourism has helped bring awareness to this species and helped to provide a way for people to see them and interact with them in a safe way when done correctly.
Image courtesy of Padiblog