What is the largest shark?

Sharks come in all shapes and sizes, from the diminutive dwarf lanternshark that reaches just 17 inches in length to the colossal whale shark that can grow over 40 feet long. But when it comes to finding the largest shark species, there are a few key contenders.

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Key Facts About Large Shark Species

Here are some quick facts about some of the largest sharks in the world:

The whale shark is the largest shark and fish species in the world, reaching lengths of up to 41 feet and weighing up to 47,000 pounds.

The basking shark is the second largest shark, growing up to 33 feet long.
The Pacific and Atlantic great white sharks rank among the largest predatory sharks, reaching lengths of up to 20 feet and weighing up to 5,000 pounds.
Megamouth sharks can grow to 18 feet long, but are relatively slender and weigh only about 2,500 pounds.

Tiger sharks and Greenland sharks can both reach 18+ feet in length and over 1 ton in weight.

The Three Largest Shark Species

Based on the maximum verified sizes, the three largest shark species are:

Whale shark

Basking shark
Pacific great white shark

Here is an overview of each of these shark giants:

Whale Shark

The whale shark (Rhincodon typus) is hands-down the largest shark and fish species on Earth. This gigantic shark reaches lengths of up to 41 feet and weights of up to 47,000 pounds.

Some key facts about whale sharks:

They are circumtropical, found in tropical and warm temperate seas worldwide.

They are filter feeders that eat tiny plankton and small fish.
Despite their massive size, they are docile sharks that pose no threat to humans.
The largest verified whale shark measured 41 feet long and weighed 47,000 pounds.

Their huge mouth can measure up to 5 feet wide.

The average size of whale sharks is more in the 25-30 foot range. But exceptional specimens over 40 feet long have been reported. Even newborn whale sharks measure about 2 feet long!

Basking Shark

The basking shark (Cetorhinus maximus) is the second largest shark and fish species in the world. These gentle plankton-eating giants reach sizes of up to 33 feet and 25,000 pounds.

Here are some key basking shark facts:

They inhabit coastal temperate waters around the world.
Like whale sharks, they are filter feeders, eating plankton, krill and small fish.

The largest verified basking shark was 33 feet long and weighed 24,000-25,000 pounds.
Their mouths can be up to 3 feet wide when feeding at the surface.
They swim slowly with their large mouths agape to filter feed.

Average sizes for basking sharks are in the 15-20 foot range. But exceptional specimens can reach and possibly exceed 33 feet.

Great White Shark

The great white shark (Carcharodon carcharias) is the largest predatory shark on Earth, reaching verified lengths of up to 20 feet and estimated weights of over 5,000 pounds.

Here are some quick great white shark facts:

They inhabit coastal waters in all major oceans.
As apex predators, they feed on seals, sea lions, fish, whales, dolphins and more.
The largest great whites have been measured at 20 feet long.

Females are larger than males.
Their mouths contain up to 300 serrated, triangular teeth arranged in multiple rows.

Great white sharks are bulkier and more robust than the plankton-eating basking and whale sharks. A 20-foot great white can weigh an estimated 4,000-5,000 pounds or more.

Other Contenders for Largest Shark

There are several other very large shark species that may potentially rival the whale, basking and great white sharks in size in rare cases:

Tiger Shark

Tiger sharks (Galeocerdo cuvier) have been reported to reach sizes of 18-22 feet and 1,000-1,900 pounds.
They are large, stoutly built sharks found in tropical and subtropical waters worldwide.

Female tiger sharks are significantly larger than males.
The largest verified tiger shark was 17.7 feet long and weighed 1,900 pounds.
But there are unverified reports of tiger sharks up to 22 feet long.

Greenland Shark

The Greenland shark (Somniosus microcephalus) is a large, slow-growing shark native to the North Atlantic.
They have been reported to reach lengths of 21-24 feet and 1 ton in weight.
However, most are much smaller, around 12-16 feet long.

The largest verified Greenland shark was 21.5 feet long and weighed 2,100 pounds.
Their extremely slow growth rate hampers validation of extra large sizes.

Pacific Sleeper Shark

The sleeper shark (Somniosus pacificus) is a close relative of the Greenland shark found in the northern Pacific Ocean.

Pacific sleeper sharks may potentially reach lengths of 20+ feet and weights near 1 ton.
But scientifically verified sizes over 15 feet are lacking for this species.

Megamouth Shark

The megamouth shark (Megachasma pelagios) is a rare, plankton-feeding species first discovered in 1976.

They are slender sharks that can reach 18 feet long, but weigh only up to 2,500 pounds.
Only a few dozen megamouth sharks have ever been documented globally.

Exact Sizes Are Hard to Verify

It is quite difficult to definitively determine maximum sizes for large sharks for the following reasons:

Finding and measuring extremely large specimens is very rare.
Many reported sizes are estimates or guesses, not verified measurements.
Scaling up from teeth or jaws often leads to overestimates of total length.

The largest individuals are almost never caught due to fisheries selectivity.

As a result, historical reports and rumors of extra large sharks over 30 feet long are unsubstantiated in many cases. Only a handful of scientifically verified measurements over 20 feet exist.

Top 3 Largest Shark Species Comparison

This table compares some key attributes of the top 3 largest shark species:

Species	Max Length	Max Weight	Habitat	Diet
Whale shark	41 feet	47,000 pounds	Circumtropical oceans	Plankton, small fish
Basking shark	33 feet	25,000 pounds	Coastal temperate oceans	Plankton, krill
Great white shark	20 feet	5,000 pounds	Coastal oceans worldwide	Seals, sea lions, fish

How Do Sharks Reach Such Extreme Sizes?

There are several biological factors that allow certain sharks to achieve such mammoth proportions:

Slow growth rates – The largest sharks grow very slowly, taking decades to reach maximum size.
Huge appetites – They need massive amounts of food to support their bulk.

Anatomical adaptations – This includes a large liver for buoyancy.
Metabolic adaptations – Some have special adaptations that lower metabolism.
Long lifespans – Long lives give more time to increase size. Whale sharks may live 70-100 years.

So their gigantic dimensions are facilitated by slow, steady growth over many years coupled with specialized adaptations that allow their bodies to function at such a massive scale.

Reproduction of Large Sharks

The reproductive habits of giant sharks also reflect their great size and slow maturation:

Gestation periods are long – up to 2-3 years for whale and basking sharks.

Litter sizes are small – whale sharks give birth to a few hundred pups while great whites average 3-14.
Reproductive age is late – 8-10 years or later.
Birth size is large – around 2 feet long for whale sharks.

Reproductive frequency is low – 3-5 years between litters.

All these factors result in relatively low reproductive outputs. But with great longevity, these giant sharks persist.

Threats and Conservation

Many of the largest shark species face substantial threats from human activities:

Overfishing – Directed fishing and bycatch deplete populations.
Ship strikes – Their large size and slow speed makes them vulnerable.
Habitat degradation – Pollution and coastal development reduce habitat quality.

Climate change – This disrupts ecosystems and food supplies.

However, there are also conservation efforts underway to protect these sharks:

Limits on large shark fishing in many regions

Designation of protected habitats
International trade restrictions under CITES
Use of satellite tags to monitor migrations

Promotion of shark ecotourism

While challenges remain, there is hope that concerted conservation action can preserve these awe-inspiring giant sharks for future generations.

Conclusion

The whale shark reigns supreme as the largest shark and fish in the ocean. The basking shark and great white also rank among shark giants. While a few other species may reach comparable sizes in extremely rare cases, these three species stand out for their sheer magnitude and regularity of immense proportions.

Yet for all their intimidating size, these sharks are fascinating creatures that play important roles in ocean ecology. Protecting these giants to ensure their survival provides benefits that extend across marine ecosystems.

When it comes to superlative size, the great whale shark truly represents the ultimate shark colossus patrolling our seas. The discovery of each new larger-than-normal individual provides a reminder of how much remains undiscovered even for these gigantic animals.