What Do Basking Sharks Eat? Their Diet Explained

The basking shark is one of the ocean’s most mysterious marine animals. They are the world’s second-largest fish, after the whale shark. Despite being related to the great white shark and having a predatory appearance, these mackerel sharks primarily survive on plankton. Let’s take a look at what basking sharks eat and the unique way they feed. 

Basking Sharks

Basking sharks (Cetorhinus maximus) are found in Arctic and temperate waters all over the world. They can grow as long as 40 feet, but typically average around 22-29 feet. These massive sharks can reach weights of over five tons. Their lifespan in the wild is unknown, but they are believed to live up to 50 years.

They are migratory sharks, sometimes traveling thousands of miles in search of food or mates. They may travel in pairs, but groups of over 100 sharks have been documented. Basking sharks are not aggressive towards humans. However, their extreme size and rough skin make it prudent to exercise caution when boating or diving.

How Does the Basking Shark Hunt for Food?

Basking sharks are one of three shark species that are known to be filter feeders. However, unlike the other two species of filter-feeding sharks, the basking shark cannot suck water through its mouth and must passively feed. They are often seen near the surface of the water, moving slowly at around 2.3mph. While it may look like they are basking in the sun, they are feeding off dense pockets of plankton near the water’s surface.

They swim through the water with their mouths open over three feet wide. Their gaping mouths filter water through their gills, and the small plankton gets captured by the gill rakers. These long, comb-like structures keep the food from escaping through their gills. Basking sharks close their mouths occasionally to swallow and filter the plankton. Some scientists believe the basking shark feeds at the surface when plankton is readily available, then sheds its gill rakers and hibernates in deeper water during the winter.

What Do Basking Sharks Eat?

Plankton is the main source of food for basking sharks. Yet, what exactly is it? Plankton is classified as a marine drifter. This means it is an organism that is unable to swim and is carried by the tide. There are two main types of plankton: phytoplankton, which are plants, and zooplankton, which are animals. The basking shark’s preferred food is zooplankton, specifically copepods. 

Copepods are microscopic crustaceans that eat phytoplankton. They have an average length of about 0.04-0.08 inches, but some can grow as large as 13 inches. Some sources believe that copepods may be the most plentiful animal species on Earth.

Basking sharks seek out copepods, but may also consume other zooplankton, such as:

• Shrimp
• Small fish
• Barnacles
• Fish eggs
• Small jellyfish
• Invertebrate larvae

How Much Do Basking Sharks Eat?

As noted earlier, adult basking sharks average 22-29 feet in length and weigh upwards of 10,000 pounds. Such enormous animals need to eat large amounts of plankton to survive.

Over 2,000 tons of water are filtered by their gills every hour. It is difficult to determine the actual amount of food that they eat in a single day, since zooplankton are so small. However, they must eat millions each day, which can easily amount to several hundred pounds in weight.