In celebration of International Whale Shark Day (Fri 30 August), this month we're showcasing the majestic Whale Shark…

This mighty shark is the biggest fish in the ocean. The largest on record was over 20m long and weighed 42 tonnes! Yet the average size of Whale Sharks today is generally much smaller.

These slow-moving giants are grey-blue in colour with a distinctive pattern of pale spots. This pattern is unique to each individual, just like human fingerprints! So, researchers can use these distinct markings to identify and then monitor individual Whale Sharks.

Whale Sharks have a huge mouth that can be up to 1.5m wide. They’re one of only three filter-feeding sharks - the others being the Megamouth and Basking Shark. Unlike Basking Sharks, Whale Sharks don’t depend on forward movement to feed, and can also suck in their food by opening their huge mouth.

They have 3000 tiny teeth, but these aren’t used for feeding. Instead Whale Sharks use long comb-like structures on their gills, known as gill-rakers. These trap and filter zooplankton as small as 1mm, such as krill, crab larvae and jellyfish. Sometimes Whale Sharks can be seen ‘coughing’, and it’s thought that this helps them clear food particles that have accumulated on their gill-rakers.

Whale Sharks are highly migratory. One was recorded travelling 13,000km in one direction over 37 months. Many individuals will return to the same locations each year. Hot spots include Western Australia, Philippines, Mexico, Belize, Costa Rica, Galapagos, St Helena, Mozambique, Seychelles and the Maldives.

In some locations they’re sighted all year round. While in other areas they’re only seen at certain times of the year. It’s thought that this behaviour is primarily guided by food. For example, every year Whale Sharks gather within the Ningaloo Marine Park, Australia, in March-April - their appearance coinciding with a coral mass spawning event.

The largest known aggregation sites host hundreds or even thousands of individuals. Their beauty and gentle demeanour inspire people to travel from all over the world to see them.

  • SCIENTIFIC NAME: Rhincodon typus

  • FAMILY: Rhincodontidae – Whale Sharks are the only member of this family


  • DIET: Plankton (mainly zooplankton) and small fish

  • DISTRIBUTION: All tropical and warm-temperate seas, except the Mediterranean.

  • HABITAT: Generally seen in open seas, where there’s plenty of zooplankton. Occasionally they venture closer to shore, entering lagoons or coral atolls. They can dive to depths of 1,928m to feed.



  1. Adopt a Whale Shark with us today and you’ll be supporting vital research by the Maldives Whale Shark Research Project (MWSRP).

  2. When booking a Whale Shark tour choose a responsible operator that follows MWSRP’S guidelines to interact safely with these sharks.

  3. Seen a Whale Shark? Record this to our Sightings Database.

Adopt a Whale Shark

Related Links:

► Check out more incredible sharks and rays covered in our Creature Features

► Discover more fin-tastic facts by visiting our Discover Sharks section

Banner image © Steve Jones