Ancient Sharks’ Cannibalistic Behavior May Have Helped Them Become Giants

KEY POINTS

  • Megalodons grew to be up to 50 feet in length
  • The prehistoric sharks were the biggest among the carnivorous or non-planktivorous shark species
  • Researchers say a unique behavior called intrauterine cannibalism may have helped megalodons grow very large

The ancient megalodon sharks’ predatory behavior inside the womb might have helped them achieve their gigantic size, a new study shows. The shark species grew to be up to 50 feet in length before going extinct about 3.6 million years ago.

In a study published in the journal Historical Biology, a team of researchers explained that most sharks give birth through a method known as ovoviviparity, where the embryos develop inside eggs that remain inside the mother’s body until they are ready to be hatched. In some aggressive shark types like lamniform, the early-hatched embryos often eat the unhatched eggs, a behavior called intrauterine cannibalism, the researchers noted. Megalodons belong

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Cannibalism in the womb may have helped make megalodon sharks giants

The largest sharks ever to hunt in Earth’s oceans may have gotten so big thanks to their predatory behavior in the womb, scientists report October 5 in Historical Biology.

The idea emerged from a study that first analyzed the sizes and shapes of modern and ancient shark teeth, using those data to estimate body sizes of the fish. Paleobiologist Kenshu Shimada of DePaul University in Chicago and colleagues focused on an order of sharks called lamniformes, of which only about 15 species still exist today, including fierce, fast great white and mako sharks as well as filter-feeding basking sharks (SN: 8/2/18).

Well over 200 lamniform species existed in the past, some of them quite large, Shimada says. But none is thought to have rivaled Otodus megalodon, commonly called megalodon, which lived between about 23 million and 2.5 million years ago. Determining just how giant these creatures were

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Female whale sharks officially named biggest fish in the sea

Whale sharkGetty Images

The largest whale shark ever recorded was 18.8m long!

Female whale sharks have officially been named the biggest fish in the sea.

The average adult length of a whale shark is eight or nine metres – that’s about 28 feet.

But for nearly 10 years, there has been an ongoing debate amongst marine experts – is the male or female whale shark bigger?

According to a new study which was published in Frontiers in Marine Science, the 10-year long analysis has concluded…and females are officially bigger.

Their average length is now 14m (metres).

That’s taller than a double-decker bus, and almost as high as the letters of the Hollywood sign, which are 15m!

The Hollywood signGetty Images

The Hollywood sign is 15m tall

A team of fish biologists at the Australian Institute of Marine Science tracked 54 individual whale sharks over the course of a decade and recorded more than

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