Image Gallery: Mysterious Lives of Whale Sharks

Whale Sharks

Whale Sharks

(Image credit: Jennifer Schmidt, University of Illinois at Chicago.)

Whale sharks are the largest fish species, ranging from 18 to 40 feet (5 to 12 m) in length. Though they live in warm waters across the globe, researchers usually get to study them only in coastal waters where young juvenile males cluster to feed. Much of the sharks' lives seem to occur in the open sea, where they're hard to observe, leaving chunks of their lives a mystery. For instance, no one has ever seen whale sharks mate.

Scooping up plankton

Whale sharks feeding

(Image credit: Jennifer Schmidt, University of Illinois at Chicago.)

While swimming, mouths open, at the water's surface, whale sharks filter the water for tiny floating plants and animals called plankton, and any small fish that get caught in their mouth filters, which are made up of a spongy tissue that is supported by cartilage rods.

Filtering water

Whale shark filter-feeding

(Image credit: Jennifer Schmidt, University of Illinois at Chicago.)

Whale sharks can filter 400,000 gallons (1.5 million liters) of water of hour, according to Sea World.

Best friends forever

whale sharks swimming in pairs

(Image credit: Jennifer Schmidt, University of Illinois at Chicago.)

Scientists have been puzzled over why hundreds of whale sharks congregate each year off Isla Mujeres, a barrier island off the Yucatan Peninsula. On numerous occasions, scientists noticed at the "afuera" (a name given to this aggregation phenomenon) the whale sharks were pair swimming. "It seemed more deliberate than just that there were lots of sharks in a small area," said Jennifer Schmidt, of the University of Illinois at Chicago who studies whale sharks, adding that perhaps they have "best friends forever" (BFFs) like us.

Whale shark fins

Feeding aggregation

(Image credit: Jennifer Schmidt, University of Illinois, Chicago)

"You see dorsal fins and tail fins for as far as the eye can see in an amazingly dense mass," said Jennifer Schmidt of the whale shark aggregations in Mexico.

Sharks from above

whale sharks from above

(Image credit: Proyecto Domino)

Aerial photo of whale sharks taken in the summer of 2009.

Big mouth

Whale shark close-up

(Image credit: Mote Marine Laboratory)

The whale shark's mouth can be up to 5 feet (1.5 m) wide, lots of room for scooping up ocean snacks.

Filter feeder

Whale shark feeding

(Image credit: Jennifer Schmidt, University of Illinois, Chicago)

A large whale sharks swims along the surface, likely getting mouthfuls of fish eggs and other plankton.

Slow-motion feeding frenzy

Whale shark feeding

(Image credit: Proyecto Domino)

An aerial photograph of sharks feeding near the Yucatan gives a sense of the scale of the shark feeding aggregations.

Swimming with sharks

Whale shark

(Image credit: Kim Hull/Mote Marine Laboratory)

Since 2003, Robert Hueter, director of Mote's Center for Shark Research has been studying whale sharks off Isla Holbox in Mexico's Yucatan Peninsula, where the sharks gather by the hundreds every year. Here he is shown in the Gulf of Sarasota getting ready to tag a whale shark.

Keeping tabs on sharks

whale shark tagging

(Image credit: Kim Hull/Mote Marine Laboratory)

Hueter swims toward a whale shark in the Gulf of Sarasota so he can tag the fish using a Hawaiian sling. The tags will help scientists learn more about the movement patterns of the whale sharks.