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How do you identify a whale shark?

Whale sharks are the largest fish in the ocean, growing up to 40 feet long. Despite their massive size, they are gentle filter feeders that pose no threat to humans. Whale sharks can be identified by their enormous size, broad flat head, checkerboard pattern of light spots and stripes, and wide mouth. Here is a guide to help identify these magnificent creatures.

What Does a Whale Shark Look Like?

Whale sharks have several distinctive physical characteristics that make them easy to identify:

  • Enormous size – Whale sharks are the largest fish in the ocean, reaching lengths of up to 40 feet and weighing up to 15 tons. They are significantly larger than most other shark species.
  • Broad, flat head – A whale shark’s head is very wide and flat, unlike most other sharks that have a pointed snout.
  • Large mouth – Whale sharks have an extremely wide mouth that can reach up to 5 feet across. Their mouth is located at the very front of their broad head.
  • Checkerboard pattern – Whale sharks are gray, brown, or blue on top with a checkerboard pattern of spots and stripes that are light yellow, white, or gold in color. No two whale sharks have the exact same pattern.
  • Small dorsal and caudal fins – Despite their massive size, whale sharks have relatively small dorsal and caudal (tail) fins compared to their large bodies.
  • Wide, flat body – Whale sharks have a wide, thick body that is flattened sideways. They are wider than they are tall.

How Big Do Whale Sharks Get?

Whale sharks are enormous in size compared to most other shark species:

  • Length – Whale sharks average 32 feet long but can reach lengths of up to 40 feet, about the size of a school bus. Anything over 30 feet is considered a very large whale shark.
  • Weight – Whale sharks commonly weigh around 15 tons (30,000 pounds). Some of the largest individuals may weigh up to 20 tons.
  • Mouth size – The mouth of a whale shark can be up to 5 feet wide.
  • Fins – The dorsal fin of a large whale shark may be up to 1.5 feet tall. Their long tails can span up to 10-12 feet across.

To put their size in perspective, whale sharks are larger than a city bus, a Tyrannosaurus rex, and a semi-truck!

Where Are Whale Sharks Found?

Whale sharks live in warm tropical and subtropical waters around the world. The specific habitats they are found in include:

  • Tropical coral reefs
  • Coastal areas
  • Lagoons and bays
  • Areas with upwellings that bring nutrient-rich water to the surface

Some key places whale sharks live and congregate include:

  • The Bay of Bengal near India
  • The Philippines
  • The Gulf of Mexico
  • Ningaloo Reef in Western Australia
  • Galapagos Islands in Ecuador
  • Gladden Spit in Belize
  • Quintana Roo, Mexico
  • Mozambique Channel in Africa

Whale sharks migrate long distances to feed and breed. Some travel over 13,000 miles per year.

What Do Whale Sharks Eat?

Whale sharks are filter feeders that eat tiny plankton, fish eggs, krill, and other small organisms by swimming with their mouths open and filtering water through their gills. A whale shark’s diet includes:

  • Plankton
  • Fish eggs and larvae
  • Jellyfish
  • Small squid, fish, and crustaceans
  • Algae and seaweed

A whale shark can filter over 6 tons of plankton daily. They do not pose a threat to humans and are gentle giants.

How Do You Identify a Baby Whale Shark?

Baby whale sharks look like miniature versions of adults. Here’s how to identify them:

  • Very small size – Newborn whale sharks may be around 2 feet long.
  • Thinner body – Babies have a thinner, more tapered body shape than mature adults.
  • Spot pattern – Babies have more pronounced spotting that fades as they age. The spots stand out more against their darker gray/brown color.
  • Proportionally larger fins – Baby whale sharks have larger dorsal and pectoral fins relative to their body size.
  • Whitish belly – Young whale sharks often have a pale whitish or yellowish belly.

As whale sharks mature, their color fades, their spots become less defined, and their body thickens.

How Long Do Whale Sharks Live?

Scientists estimate whale sharks may live around 70-100 years. However, their lifespan is still not precisely known. Factors that make determining their age difficult include:

  • Slow growth rate – Whale sharks reach maturity around 30 years of age. They grow slowly throughout their long lives.
  • No internal rings – Some shark species have internal rings in their vertebrae that indicate age. Whale sharks do not have these growth rings.
  • Constantly replaced teeth – Whale sharks continually shed and replace their thousands of filter teeth, so teeth wear cannot indicate age.

Recent studies using carbon-14 dating have estimated ages of 50-80 years for large adults. More research is needed to understand longevity.

How Many Whale Sharks Are Left in the Wild?

Whale shark populations are declining. However, because they are migratory and span huge ranges, their exact population numbers are uncertain. Current estimates include:

  • Less than 10,000 individuals in the Atlantic Ocean
  • Around 130,000 in the Indo-Pacific region
  • Classified as Endangered by the IUCN Red List due to 50-79% population declines

Major threats to whale sharks include boat collisions, fishing nets, pollution, and habitat loss. More conservation efforts are crucial for whale shark survival.

Interesting Facts About Whale Sharks

Here are some additional intriguing facts about these gentle ocean giants:

  • Whale sharks have blue blood, just like many other shark species.
  • Up to 300 tiny teeth line a whale shark’s mouth in rows used for filter feeding.
  • Whale sharks have a remora fish called sharksuckers that hitch rides on their massive bodies.
  • Their checkerboard pattern of spots and stripes provides camouflage in the water column.
  • Whale sharks can dive up to almost 2 miles deep, but usually swim near the surface.
  • Whale sharks are ovoviviparous – the eggs hatch inside the female’s body.


In summary, whale sharks are the largest fish in the sea and one of the most iconic shark species. They can be identified by key features like their massive size, broad head, checkerboard color pattern, wide mouth, and small fins. Whale sharks are filter feeders that migrate long distances and mainly inhabit tropical waters. Learning to identify these amazing creatures is the first step in being able to appreciate and help protect whale sharks when encountered.

Whale Shark Fact Description
Maximum length Up to 40 feet
Maximum weight Up to 15-20 tons
Lifespan Estimated 70-100 years
Diet Plankton, fish eggs, jellyfish, krill, algae
Key habitats Tropical coral reefs, coastal areas, lagoons
Conservation status Endangered