Whale Shark: The World’s Largest Fish

by AMNH on

On Exhibit posts

One of the most interesting “whales” on display in the American Museum of Natural History isn’t a whale at all—it’s a fish called the whale shark.

It can be seen in the Irma and Paul Milstein Family Hall of Ocean Life, which is currently celebrating its 10th anniversary. Just peek past the tail of the blue whale to a spot high on the wall beneath an arch to the right at the back of the hall.


Unlike whales, sharks are not mammals but belong to a group of cartilaginous fishes. The whale shark (Rhincodon typus) earns the name “whale” solely because of its size.

Just as the blue whale (Balaenoptera musculus) is the largest living mammal*, the whale shark is the largest species of any fish, known to reach more than 40 feet in length.

Besides sharing the title of biggest among their kind, the blue whale and whale shark have something else in common. They are both filter feeders. The blue whale lives mostly on small shrimp-like crustaceans called krill, which it strains from sea water through baleen, a fringe made of keratin, the same material that makes up human fingernails.

The blue whale model in the Milstein Hall of Ocean Life is 94 feet long.
© AMNH/D. Finnin

Whale sharks also consume krill, other zooplankton, fish eggs, and small fishes by bobbing up and down near the water surface to pump prey-filled water over their gills or swimming with their wide mouths agape.

Whale shark
Whale sharks often feed passively, by swimming with their large mouths open. 
Jon Hanson

Despite their other name—shark—these giants are so gentle that snorkelers and scuba divers seek them out to swim alongside them. The whale shark is listed as “Vulnerable” on the International Union for Conservation of Nature Red List of Threatened Species due to threats from commercial fishing, but the growth of whale-shark tourism may lead some communities to see them as more valuable alive.

*In addition to being the largest mammals living today, blue whales are the largest animals, of any kind, that ever lived! To learn more about true whales, visit the special exhibition Whales: Giants of the Deep, now open.