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Home › Ocean Life › Marine › Vertebrates › Sharks › Whale Shark

Information about the Whale Shark

[Phylum: Chordata] [Class: Chondrichthyes] [Order: Orectolobiformes] [Family: Rhincodontidae]

Whale sharks are unmistakably the largest living fish in the animal kingdom. In fact, individual species can weigh 20 metric tons and grow up to 18 metres long (60 feet).

This guide contains fun and interesting facts about whale shark species (Rhincodon typus), including where these colossal vertebrates still exist, what they eat, and how they reproduce.

Whale Sharks Habitat and Key Distribution

Let's begin by confirming the most common places to find whale sharks around the world.

It is an enormous pelagic fish that favours warm water environments, especially coastal and oceanic habitats near:

• Australia (e.g. Ningaloo Marine Park)
• Central America (Belize, Honduras, Mexico, Yucatan)
• India (especially the Maldive Islands)
• Southeast Asia (including Indonesia and Thailand)

By and large, they thrive better in shallow coastal ecosystems and in the lagoon areas of coral reefs and sheltered ring-shaped islands (atolls).

However, the whale shark is a highly migratory creature that often travels thousands of kilometres over a period of several years.

Interesting Fact: Scientists tagged a whale shark and tracked its migration pattern for 841 days as it covered a total distance of 12,000 miles (over 19,000 kilometres).

Whale Shark Behavior and Characteristics

The mouth of a whale shark can be over a metre wide (4 feet) and contain 300 rows of vestigial teeth. But, whale sharks do not attack or eat humans. In actual fact, despite being a shark (not a whale), these "gentle giants" are not aggressive at all.

There are no recordings of whale sharks attacking swimmers or divers, even though they often get close enough to take photographs of them in the water.

Put another way:

The whale shark's characteristics and behaviour towards mankind is unthreatening. On the contrary, in some rare instances, their docile and approachable relationship with swimmers can even be quite a playful one!

In biological terms, some of the bottom-dwelling sharks (e.g. carpet sharks and the wobbegong) are their closest relatives.

Whale sharks are cartilaginous, meaning they do not have the typical 'fish-like' skeleton backbone. Similar to most shark species and batoid marine rays, a tough, yet flexible, tissue called cartilage forms their whale-like structure and skeletal outline or shape.

Here's the thing...

A distinct pattern of white spots and stripes on blue skin disperses sunlight and helps them blend in with oceanic tropical environments.

In practice, marine biologists use this unique skin patterning (similar to fingerprints) to identify individual whale sharks.

Being a large fish means they have extra large gills. So, as water enters the mouth they absorb dissolved oxygen and dispel carbon dioxide.

Unlike most marine mammals, such as dolphins and whales, whale sharks have no physiological need to swim near the surface. As a consequence, they can dive to depths approaching seven hundred (700) metres (2,300 feet) and stay submerged for long periods.

Pro Tip: It is common to see other large fish swimming around Rhincodon typus for protection, especially cobias and remoras (suckerfish).

Whale Shark Size and Weight

So, how big is a whale shark and what is the heaviest they can weigh? Well, despite being the largest fish in the world, these cold-blooded animals are actually slow swimmers - averaging 3 mph.

But, fully grown adult whale sharks can be more than twenty metres long (60 feet) and weigh more than twenty (20) tonnes (over 18,000 kilograms).

In fact, the common name "whale shark" comes from these two record breaking physiological facts and their voracious feeding habits.

What Does a Whale Shark Eat?

These huge filter-feeders use passive ram filtration or active suction. Both methods allow them to eat their favourite diet, microscopic plankton, even while stationary or vertical.

Hence, three hundred rows of atrophied teeth serve no real function when they eat. Instead, they use twenty or so filter pads to sieve suspended food matter from the water column.

Because they are unable to bite or chew their prey, filtering 6,000 litres of saltwater per hour is a labour intensive task.

Even so, they slowly meander a few metres below the surface, they open their gigantic mouth, and then they use the fine mesh inside their gill rakers to sift minute organisms, which may include:

• Crab larvae (including Christmas Island red crab)
• Egg spawn
• Jellyfish
• Krill
• Planktonic material
• Small fish
• Nektonic life (e.g. Squid)
• Tiny crustaceans (e.g. copepods, sea shrimps)

Besides the whale shark species (Rhincodon typus), there are only two other filter-feeding sharks, that being the basking shark and the megamouth shark.

Fun Fact: Despite the unequaled size and weight of the biggest fish in the sea, whale sharks do not prey on other aquatic mammal species or large fishes.

Whale Shark Breeding

Their reproductive process reveals several interesting facts about whale sharks. For example, males tend to grow faster than females, especially during the early stages of development.

Plus, sexual maturity arrives late and adults will not start breeding until they are at least twenty five (25) years of age and have reached at least eight (8) metres in length.

In case you were wondering:

Whale sharks exhibit internal fertilisation and produce live young. As the eggs develop, they will remain inside the female before hatching "internally". A whale shark egg is about fifteen (15) centimetres long (6 inches) and twelve centimetres wide.

Baby whale sharks are called pups and they are surprisingly small when they're first born. Juveniles are less than one metre in length when they hatch from eggs.

How to Spot a Female Whale Shark?

Unlike the majority of fish families, it's easy to spot the difference between male and female sharks. Only the male whale shark has a pair of claspers. These organs are rolls of calcium cartilage located near the pelvic fin and used during the mating rituals.

These appendages are not present in females. In addition, the female whale shark fish is usually a lot bigger than the male.

Threats and Predators

In fact, scientists believe less than 10 percent of newborn whale sharks will actually survive all the way through to adulthood. But those that do, may actually live as long as most human beings.

Even though a whale shark lifespan can be one hundred (100) years, the average age is around fifty (50). At this time, they remain among the list of vulnerable species. They are still hunted down and killed for their fins in some Asian countries.

In contrast to the whale shark fun facts in this report, there are several reasons why the survival of many sharks is under threat, including:

• Climate change (e.g. Ocean acidification)
• Human behaviour (fish bycatch)
• Underwater plastic and garbage pollution

Important: According to the IUCN Red List of Threatened Species, a recent assessment (February 2024) for the whale shark (Rhincodon typus) lists the species as decreasing in numbers and "Largely Depleted" (LD). Despite this, many shark conservation groups consider their survival as being "threatened with extinction".

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