August 30th is International Whale Shark Day! Though their name can be confusing to some, these animals are sharks, not whales. Their name is a reference to their size: these majestic gentle giants of the ocean are the largest fish in the world, growing over 40 feet long. Despite their large size, they are completely harmless to humans.
Their name also references their distinctive feeding method, which resembles that of baleen w hales. These massive sharks are filter feeders, eating only plankton and small fish by inhaling huge amounts of water through the mouth, straining out the tiny organisms before expelling the water out through their gills. Only two other species of shark are known to be filter feeders: the basking shark and the megamouth.
But the whale shark isn’t closely related to either of those sharks. They belong to a group called “carpet sharks”, which also includes the nurse shark and zebra shark. The name comes from the fact that most of the sharks within this order are brightly patterned like a carpet, and are also known for their habit of lying like a rug on the seafloor. While sharks do possess a unique pattern of spots and stripes, they swim freely in the open sea unlike most other carpet sharks.
Whale sharks are found in warm waters worldwide, usually in the open ocean near the surface, although they occasionally dive to deeper depths, sometimes more than a mile down. Though they are primarily an offshore species, they are known to gather in large groups near certain coastal areas to feed. In 2011 more than 400 of these giants gathered off the coast of Yucatan in Mexico. Many of these areas have become popular spots for ecotourism, drawing countless tourists who wish to see these fish in person. While this does help to raise awareness of these amazing creatures, it can also cause harm to the sharks as increased boating activity in their feeding areas can lead to collisions.
Such collisions are one of the many reasons that whale sharks are currently considered endangered. They are also sometimes caught in fishing nets intended for other species. They are a long-lived species that may live as long as 70 years, and they reach maturity slowly, so their populations are particularly vulnerable. Some countries, such as the Philippines, have introduced laws that protect sharks from being caught, fished or harassed. These gentle, easygoing creatures need all the help they can get, so that they will continue to swim the seas for centuries to come.
Bernie’s Bonus Fun Fact: In Indonesia, fishermen consider whale sharks to be omens of good luck, and believe their presence will bring good fortune.