Whale shark

The biggest fish in the world — and the gentlest

The whale shark is the biggest fish in the world — 12 metres, as long as a bus! But it harms no one — it swims with its mouth open and filters plankton and tiny fish. Its mouth is 1.5 m wide, but its throat is the size of a coin. The white spots on its skin are different on every shark — like fingerprints. People swim alongside them!

The whale shark (Rhincodon typus) is 12 m (record 18.8 m) and 20 tonnes — the filter-feeding giant of tropical oceans. Its mouth is 1.5 m wide with 300 rows of tiny unused teeth; 20 filter pads strain plankton from 6,000 litres of water an hour. Its spot pattern is unique — scientists identify individuals with an algorithm designed for star maps. It dives to 1,900 m and migrates 10,000 km a year. It gives birth to live young — up to 300 (in a female found in 1996). It lives 100–150 years and matures at 30. Fishing nets, ship strikes and the fin trade have cut numbers by 50% in 75 years. Ningaloo (Australia), Mexico and the Philippines are centres of whale-shark tourism.

Fun facts

• Scientists tell whale sharks apart using star-recognition software!
• Its mouth is 1.5 m wide but its throat is coin-sized — it can't swallow a person.
• A whale shark lives 150 years and 'grows up' at 30.