Of the many species of shark in the world’s oceans, the basking shark is one of the most interesting. They are well known for their large size, reaching up to 36 feet in length, and for their very large mouth, with a width of up to 3.3 feet.

They travel at slow speeds, around 2 miles an hour, with their mouths open, filtering everything from plankton to invertebrates and small fish. Although they are often mistaken for great white sharks, they are two very different species. 


What is a Basking Shark?

Basking sharks are one of the world’s largest kinds of sharks, second only to the megamouth shark. It is one of three sharks that eats plankton and is found in all the world’s temperate oceans. Despite its size, the shark is a slow-moving, migratory filter feeder. They are not aggressive towards humans. They are known to move at around 3.7 kilometers an hour, or 2.3 miles. 

Basking sharks are thought to be active all year long, even during the winter when they live in the ocean’s depths. 

An illustration of an adult basking shark
An illustration of an adult basking shark


Appearance 

The basking shark has one of the most unique appearances within the world’s oceans. They are large, growing to around 26 feet, have gray to brown modeled skin, and a very large mouth which the sharks use to filter feed.

The largest examples of basking sharks have been recorded between 30 to 36 feet. But, this is somewhat unusual. Most reach lengths of a round 26 feet and weigh 4.58 long tons or 5.13 short tons. The largest recorded basking shark weighed 16 long tons or 18 short tons. 

They have long, streamlined bodies and are sometimes mistaken for great white sharks. But, their large jaws, which can measure over 3 feet in width, are their most distinguishing features. 

A basking shark opens its mouth while it swims to filter food
A basking shark opens its mouth while it swims to filter food

They also have very obvious, large gill slits that nearly circle the entire heads. The sharks have large dorsal fins, which are sometimes seen flopped over if the shark is especially large. Often, scientists come upon basking sharks with clear scars from smaller cookie-cutter sharks.

Amazingly, despite their large size, these sharks have been known to breach or jump entirely out of the water. Scientists believe that this behavior is inspired by their desire to shake off parasites.

Habitat 

Basking sharks are a widespread species. They are pelagic animals living in all of the world’s temperate oceans. Most commonly, they live in waters between 200 to 2000 m deep. They often stay close to the shoreline, and most specimens are in the Atlantic and Pacific Oceans. 

Most basking sharks are solitary creatures. But, scientists have observed larger groups of these sharks moving together during the summer. Groups of basking sharks as large as 100 members have been seen. Sometimes, in sex-segregated groups. But, it’s far more common to find them in small groups or alone. 

The head of a basking shark and its unique snout
The head of a basking shark and its unique snout


Diet 

Basking sharks are known as ram feeders. This means that they filter feed on plankton, small fish, and even invertebrates. They use their gill rakers to filter food from the water as they swim, moving it easily into their mouths. 

Reproduction 

Like many sharks, basking sharks are ovoviviparous, meaning they give birth to live young (in comparison, only 40% of sharks lay eggs) during the summer with a gestation period of between 2-3 years. The young are up to 6 feet long when they’re born. Unfortunately, like many of the ocean’s amazing creatures, little is known about basking sharks’ reproductive habits.

Predators and Threats 

Because of their size, basking sharks have a few predators. More often, these sharks serve as a source of food for a variety of smaller meat-eating animals after their deaths. One of the only possible predators the sharks may have is orcas, or killer whales, which have been observed feeding on them.

While they may not face many threats from traditional predators, as many smaller species of shark do, basking sharks are threatened by human-caused dangers. These include boat collisions, getting entangled in fishing nets, and even hunting for commercial markets. 

Interesting Facts about Basking Sharks

  • Basking sharks are the second-largest species of shark. 
  • They are one of three species that feed on plankton. 
  • They have one of the largest mouths of any shark species. 
  • These sharks are found in all of the world’s temperate oceans. 
  • Basking sharks look aggressive but pose no threat to humans. 
  • It’s common to find basking sharks near the shoreline. 
  • Most basking sharks live in the Pacific Ocean and the Atlantic Ocean. 


FAQs 

What are two major threats facing basking shark populations?

The two threats basking shark populations face or entanglement in fishing and collisions with large vessels. These issues faced many of the ocean’s largest species, including many shark species.

Do basking sharks have enemies?

The only real enemies or predators basking sharks have to deal with are killer whales and human beings. While some large sharks may pose a threat, it’s rare that any shark species would want to take on the very large basking shark.

What shark keeps its mouth open?

The basking shark is best known for swimming with its mouth open allowing small fish, invertebrates, and plankton to flow through its gills. It is one of three sharks that feed in this manner.

How many basking sharks are left?

Sadly, to historic hunting practices and contemporary problems with vessel collisions and net entanglement, there are believed to be around 10,000 basking sharks left in the world’s oceans. They are listed as “endangered” by the IUCN. 

Are basking sharks aggressive?

No, basking sharks, despite their large size, are not aggressive towards humans. They are also very slow moving, swimming no faster than around 2 miles an hour. They have no interest in eating large prey.