Pictures: Biggest Whale Shark "Swarm" Found

Swarm From the Sky

Photograph courtesy Smithsonian Institution

Looking like rice grains, four boats carefully weave through the 2009 whale shark swarm in an aerial picture.

There's no evidence the fish were interacting or working together to catch more food, as dolphins sometimes do by herding schools of fish, Maslanka said. "They're big animals, but their brains aren't all that big."

But the assembly did reveal a new spawning ground for little tunny—as well as a new aspect of whale shark behavior, he said.

Instead of stuffing themselves to the gills and moving on after one spawning event, as scientists had suspected, the sharks hung around for a while to take advantage of successive spawnings.

(See more shark pictures.)

Published June 13, 2011

Working Lunch

Photograph by Mauricio Handler, National Geographic

A photographer snaps a whale shark feeding near Isla Mujeres, Mexico, in an undated picture taken during a separate whale shark aggregation.

Whale sharks predictably congregate along Mexico's eastern coast each summer, but where they roam the rest of the year remains a puzzle, Maslanka noted.

"How populations are linked, if they're linked, what mixing takes place in terms of genes, whether there's any passage between the Atlantic and Pacific populations—it all still remains to be seen."

(See "NASA Tool Helps Track Whale Sharks, Polar Bears.")

Published June 13, 2011

Filter Feeder

Photograph by Mauricio Handler, National Geographic

The whale shark (like this one pictured off Mexico's Isla Mujeres in an undated photo) is a filter feeder.

To gather its food, the beast juts out its formidable jaws to take in plankton-filled water. It then closes its mouth and opens its gill flaps, using the tooth-like dermal denticles lining its gills as a sieve to catch any organisms bigger than two to three millimeters wide.

(Watch a video of a whale shark feeding.)

Published June 13, 2011

Among Giants

Photograph by Mauricio Handler, National Geographic

Snorkelers swim with whale sharks off Isla Mujeres in an undated file picture.

Whale shark ecotourism is blooming in this region of Mexico, which is close to the major tourism hub of Cancún, Maslanka said.

Overall, tour companies have done well in establishing rules to keep the whale sharks safe—for example by not allowing people to touch the sharks and limiting the number of swimmers in the water at one time.

"It's a very easy and accessible wildlife experience for people in North America," he said. (Related video: "Swimming With Giant Whale Sharks.")

Published June 13, 2011

Whale of a Time

Photograph by Mauricio Handler, National Geographic

In a file picture, snorkelers and whale sharks surround a boat in Isla Mujeres.

Due to fishing, the whale shark is listed as "vulnerable" by the International Union for Conservation of Nature. The animals continue to be hunted in parts of Asia, primarily for their meat, liver oil, and fins.

(Related: "World's Largest Shark Species at Risk, Expert Says.")

Published June 13, 2011