Whale Shark: is it a Whale or a Shark?

Whale sharks are one of the most fascinating and unique species on the planet. With their enormous size, distinctive pattern, and gentle demeanor, whale sharks are iconic and easily recognizable by most people.

However, despite their name, these creatures are not whales at all but are instead the largest species of shark in the world. Let’s dive a bit deeper into the life of these gentle giants.

Classification and Anatomy

Whale sharks belong to the Chondrichthyes class, which includes all species of cartilaginous fish, such as sharks, rays, and skates. The whale shark's anatomy is typical of a shark, with a streamlined body, large triangular dorsal fin, and five to seven gill slits on the sides of its head. However, what sets the whale shark apart from other species of shark is its enormous size, one of the biggest in the ocean. The average length of a mature whale shark is between 5 and 9 meters long, but some individuals can grow much bigger. The biggest ever reported whale shark was 18,8 meters long.

While whale sharks look huge, their brain-to-size ratio is smaller than a lot of other big sea life. So it might be fair to say that they are probably not the smartest of sharks!

Their distinctive pattern is unique to each individual: a section close to the gills is the unique ID of each whale shark. They are identified and tracked with the help of photos from all over the world sent by divers and snorkelers in the Wildbook for Sharks.

Not so small baby shark

Unlike whales, whale sharks are oviparous, meaning the female produces eggs that grow and develop inside her body, giving birth to formed young animals.

There is a lack of precise data on the whale shark’s reproduction, as pupping has never been witnessed, but scientists believe that female whale sharks give birth to young fully formed whale sharks about 50/60cm long.

The ones who survive predators grow into full-size adults over several years. Current research indicates that females reach sexual maturity around 20 years old and that individuals in the wild can live up to 100 years old.

Diet and Feeding Habits

Despite their massive size, whale sharks are filter feeders (like most whales, maybe the reason for their confusing name?) and feed on some of the smallest creatures in the ocean: plankton, krill, and small fish. They have a large mouth that opens wide to take in massive amounts of water, filtering out the plankton and other small creatures through their gill rakers. They have been known to consume up to 300kg of food per day!

The pattern on each animal is unique

Geographic Repartition

Whale sharks are found in tropical and subtropical waters around the world, primarily in the Atlantic, Pacific, and Indian Oceans. They are known to migrate long distances, with some individuals traveling thousands of km in a single year. Periodically during the year, whale sharks are often found in areas with high concentrations of plankton, which they feed on. Data indicates that in the winter, they move to warmer waters to breed and give birth to their young.

Thinking about snorkeling or diving with whale sharks? Check out this article where you can find the best spots to do so!

Behavior and Social Habits

Whale sharks are solitary creatures, rarely seen in groups. However, for feeding they might regroup in areas where plankton or krill is abundant. They are not territorial and will often be found swimming alongside other whale sharks. They are generally slow-moving and docile and have been known to approach divers and boats. Of course, like any other marine life, it is important to keep some distance from whale sharks and not touch or harass them in any way.

Conservation and Threats

Whale sharks are listed as an endangered species by the International Union for Conservation of Nature (IUCN). The biggest threats to their populations include fishing for fins and other parts, accidental entanglement in fishing gear, and the degradation of their habitats.

There are very few predators of whale sharks given their huge size, those include orcas or big shark species like great white sharks.

Whale sharks are genuinely one of the most impressive, yet still mysterious species on the planet. Despite their name, they are not whales but are instead the largest species of shark in the world, yet probably the most gentle one! If you ever get the chance to see one in the ocean, you will likely never forget it!