Cookiecutter Shark

Cookiecutter sharks are squaliform sharks.

Squaliform sharks have two dorsal fins. Squaliform sharks usually have five to seven gill slits on their sides. They also typically do not have anal fins.

5 Incredible Cookiecutter Shark Facts

• These sharks have the largest teeth of any shark species at any location. Like all sharks, it loses its teeth and grows new ones throughout its life.
• The liver accounts for 35% of the sharks’ weight. The liver contains low-density lipids that help this shark float.
• The underside of the shark is covered in photophores that give this shark an eerie green glow. The glow lasts for up to 3 hours after the shark dies..
• These sharks are parasitic. They often bite out a cookie-shaped hole in a much larger fish.
• These sharks have bitten through submarines. They have bitten soft areas, like electrical cables and rubber sonar domes.

Classification and Scientific Name

The scientific name of the cookiecutter shark is Isistius brasiliensis. There are two species of cookiecutter sharks. The Isistius brasiliensis is called the cookiecutter shark while the Isistius plutodus is called the large cookiecutter shark. They are members of the Isistius genus.

All of these sharks are members of the Dalatiidae family. This family is more commonly referred to as the kitefin shark family. They are also members of the Squaliformes includes over 125 fish species. Like other fish with a spine primarily made of cartilage, they are part of the Chondrichthyes order. They belong to the Chordate phylum order and the Animalia kingdom.

Species

There are two species of these sharks. There have been only about 10 largetooth cookiecutter sharks caught, so very little is known about them.

Scientists believe that the largetooth cookiecutter shark has larger teeth, especially on the lower jaw, than the cookiecutter shark. They also think that the largetooth shark is a weaker swimmer than the cookiecutter shark. They both live in diverse locations globally.

Evolution

Like other shark species, experts believe that cookiecutter sharks evolved from ancestors in the Earth’s oceans more than 400 million years ago. They are classified Dalatiidae, the dogfish shark family, which is a primitive species. Cookiecutter sharks date back at least 100 million years. 

Appearance

These sharks are light brown. It has a long slender shape, like a cigar, which is why it is often called the cigar shark. This shark has a short, blunt snout and large eyes. It has two spineless dorsal fins and a large caudal fin.

Covering the shark’s underside are photophores. This makes the fish appear to glow when viewed from the bottom. It will continue to glow for about 3 hours after the shark is dead.

Female sharks are larger than males in size. The average male is 14 inches long while the average female is 16 inches long.

Distribution, Population, and Habitat

These sharks are found throughout the world. Their habitat is coastal areas near islands, typically warm, deeper waters during the day, keeping below 1000 meters in day hours, but have been found as deep as 3500 meters. They migrate to more shallow waters at night at a depth of around 300 meters.

The International Union for Conservation of Nature lists this species as a species of least concern. There are no accurate numbers of how many of these sharks are in locations around the world.

Predators and Prey

The cookie-cutter shark will prey on almost any marine living creature. It closes its suctorial lips against the prey, kind of like kissing it. Then, it uses its upper pointed teeth and powerful jaws to grip the prey better. Finally, it uses its upper teeth and jaws to take a chunk out of the animal. Most bites from the teeth and jaws measure about 2 inches across and 2.75 inches tall.

Many different animals have been spotted with this shark’s marks on their bodies, including porpoises, dolphins, whales, seals, sharks, stingrays, and bony fish.

Additionally, these sharks have eaten squid as big as themselves. They swallow these animals whole.

Reproduction and Lifespan

Scientists are not sure how long the gestation period is in these sharks. A shark baby is called a pup. They live inside the mother’s uterus. Six-to-12 pups are born as a baby at the same time, with each one measuring between 5.5-and-5.9 inches long when they are born. Each baby is in a sizable sac, so scientists theorize that this shark has a long gestation period.

Even though they may end up with a piece of their bodies missing, some animals eat these sharks. These animals include bony fish and sharks that are larger than them.

Fishing and Cooking

Except for a few caught accidentally, these sharks are not targeted by recreational or commercial anglers.

Population

No one has an accurate count of the number of these sharks.