How big are whale sharks? And four other whale shark facts

whale shark

1. They’re not whales, but the world’s largest fish

These huge creatures can grow up to 39 feet long. But despite their size, whale sharks are often referred to as "gentle giants."

2. Eating is laborious work

Whale sharks are filter feeders and can neither bite nor chew. They can process more than 1585 gallons of water an hour through their gills. Although its mouth can stretch to four feet wide, a whale shark’s teeth are so tiny that they can only eat small shrimp, fish, and plankton by using their gill rakers as a suction filter.

3. They can be very old

It's thought that less than 10% of whale sharks born survive to adulthood, but those that do may live to 150.

4. They’re slow swimmers and migrate a long way

With the exception of the Mediterranean Sea, whale sharks can be found in all temperate and tropical oceans around the world and migrate thousands of miles to different feeding grounds. But moving is slow going, as they move at speeds of little more than 3 miles per hour.

5. Along with other sharks, they’re under threat

Many sharks are accidentally caught in fishing gear, as well as caught deliberately for their fins, which are a delicacy in Asia. Their ocean home is also in danger. From climate change warming the water - affecting both habitats, prey, and shark population shifts - to plastic pollution, which could cause entanglement or be ingested, especially by filter feeders.

Mafia Island, Tanzania

Whale shark tourism is one of the key sources of income to the community around Mafia Island, Tanzania, with peak whale shark sighting season running from October to March. Thanks to the rich feeding grounds here, these whale sharks are permanent residents, rather than migratory like most other whale sharks.

Working with local communities, fisherfolk, and the tourism industry, WWF helps improve sustainable livelihood opportunities through the conservation of whale sharks. WWF is also monitoring these sharks and conducts surveys every couple of years to check that their population is thriving. In 2012 there were 100 individuals. Now there are around 180 – this is a great achievement considering sharks are slow to grow and reproduce.

WWF's work

Around the world, WWF is working to better protect and manage our oceans – including vital shark habitats. We’re also working to reduce bycatch and stop the illegal trade in shark products.

We can all play our part to reduce plastic pollution and fight devastating climate change, which is affecting both people and wildlife.