Eating Their Own Kind: Are Sharks Cannibals?

are sharks cannibals

Sharks are some of the most fascinating animals on the planet. With incredible sensory organs and the ability to detect blood from up to a quarter-mile away, these predators are at the top of the food chain.

They can be found in warm, tropical waters as well as the icy waters of the Arctic, often feeding on fish, shrimp, squid, crustaceans, and even other sharks.

Today, we will take a closer look at shark cannibalism and answer a question that many of our readers are eager to learn about. Are sharks cannibals?

Yes, all sharks are cannibals. It’s not unusual for even the biggest sharks to chomp down on members of their own families, and it starts at the earliest stage of life, in the womb.

Are Sharks Actually Cannibals?

Over millions of years, sharks have evolved and developed a taste for a wide variety of marine life, including other sharks.

All species of sharks are cannibals. Many sharks will feed on their own species when congregating in large numbers, often picking off the weak and injured of their own species.

Sharks are opportunistic feeders that will take advantage of any food source that is available to them when hungry, even their own kind.

Feeding frenzies happen when large sharks congregate in areas such as the Great Barrier Reef. Larger sharks such as bull sharks may attack a weak or injured smaller shark, starting a feeding frenzy.

Many other sharks will pile in, taking a bite out of the weak shark for an easy snack, and within seconds a fully grown shark can be devoured by its own kind.

Do Sharks Eat Their Siblings?

Female Sand Tiger sharks have two wombs and often conceive six or seven embryos in each womb at once, but they only give birth to two pups.

This baffled scientists until new technology revealed that as soon as the oldest embryo develops eyes and teeth, it hunts and kills its siblings in the womb.

When the largest embryo yolk sac runs dry, a tiny sand shark will rely on hunting instinct and a set of tiny teeth to begin hunting its brothers and sisters.

Although blind, the shark can sense its younger siblings using its electro-sensing ability to detect heartbeats.

The crowded womb quickly becomes home to one single living embryo that is growing stronger by the day.

Food that was once in short supply becomes plentiful, as the embryo begins to feed on the yolk sacs of its brothers and sisters as well as their remains.

From this point on, the mother Sand Tiger shark will produce no further embryos, and instead, all of her resources will go to the surviving offspring.

The mother continues to produce unfertilized eggs for her mature embryo to eat. It continues to grow rapidly in this eggy soup, swallowing up the yolk as well as the bodies of its siblings.

The sand tiger shark’s taste for its own kind continues throughout its lifetime.

Why Are Sharks Cannibals?

Ovoviviparous shark pups depend on yolk for nutrition, and when an embryo has exhausted its own yolk sac, it turns to the eggs around it to eat.

It’s survival of the fittest in the womb, and once the oldest embryo develops teeth and the ability to sense prey around it, cannibalism begins.

Approximately 14 species of shark are thought to practice some form of intrauterine cannibalism.

But it’s not just sharks in the womb that cannibalize each other. Some of the largest and most feared species of shark have been known to eat one another.

Incredibly rare footage on the National Geographic documentary ‘Cannibal Sharks’ shows two giant Great White sharks biting chunks out of one another.

In recent years, more and more shark carcasses that have been severely mutilated are being pulled out of the ocean around Australia’s Gold Coast.

But why?

Professor Mark Meekan from the Australian Institute for Marine Science has a theory that is to do with measures to keep hungry predators away from swimmers.

As part of the Gold Coasts’ safety measures to protect swimmers from sharks, nets and bated hook lines are deployed in the surrounding areas.

But these hooked sharks send out distressing signals to other sharks in the area that can benefit from a quick meal.

Sharks have the ability to sense the heartbeats of prey through electromagnetic senses, meaning they’ll come from afar to feed on hooked prey, including that of their own kind.

However, new research shows that sharks have been eating each other for millennia. An examination of fossilized poo taken from the prehistoric orthacanthus – a shark that swam in the ocean 300 million years ago – found it contained fossilized baby shark teeth.

Sharks don’t look at other sharks like they are the same species. They see prey.

There is a reason these animals are top apex predators and it’s because they will take advantage of any food source they can, even if it means eating their own kind.

Which Sharks Are Cannibals?

Mark Meekan reveals that ALL sharks are cannibals. He said, “it’s not just one rogue shark attacking other sharks or even one species of shark attacking other sharks, it’s a lot of different sharks turning on each other.”

Shark cannibalism has been around for millions of years and has allowed these animals to continue thriving in their ocean habitats.

Great White sharks, Hammerhead sharks, Tiger sharks, and Bull sharks all have a reputation for eating other sharks.

When you’re a top apex predator in the ocean, there are not many food sources that you’ll turn down.

Final Thoughts

So are sharks cannibals? Yes, all species of sharks are cannibals. Sharks attack and feed on one another when they believe they can grab an easy meal.

They will often feed on smaller sharks that are sick or injured, and once one shark attacks, many more will pile in for a bite.

Shark cannibalism even begins in the womb with some species such as the Sand Tiger shark.

This shark, despite having many embryos and two wombs will only have two shark pups, as the largest embryo of each womb will begin cannibalizing its siblings once it grows teeth.

Hopefully, this post has been informative and you’ve learned something new today about shark cannibalism.

Thanks for taking the time to read this article and if you’ve found it valuable feel free to stick around to learn more about the many other types of marine life that we discuss here.