The small sharks that damaged a catamaran off the coast of Cairns have been described as “pencils with teeth” and they have a history of trying to eat inanimate objects, including submarines.
Three people were rescued from the inflatable vessel and the Russian Geographic Society – which was involved with the sailors’ round-the-world expedition – confirmed the hull was attacked by cookiecutter sharks in the Coral Sea.
Marine biologists believe the attack was “a classic case of mistaken identity” from a “supercool” little shark that glows in the dark and has a very big attitude, despite its size.
What is that?
It’s not pretty, is it? Daryl McPhee, an associate professor of environmental science at Bond University, said cookiecutters are usually about 15-20cm long but can reach 50cm. He said they “really just look like a pencil with teeth”.
“They’ll find a large animal like a whale or a dolphin, living or dead, and attach themselves to it. They’ll twist and literally pull out a biscuit-sized chunks of flesh. They can do that repeatedly,” McPhee said.
Prof Jodie Rummer, a marine biologist at James Cook University, said the cookiecutter was technically a parasite and behaved very differently to other sharks.
“They’re called the cookiecutter shark because they don’t actually swallow their prey,” Rummer said. “They just take little bite-size morsels out of the side of them.
“They’re bioluminescent too, they glow. They’re a really cool species of shark. This unfortunate incident has given us an opportunity to learn about them.”
Will this thing kill me?
No. But an encounter wouldn’t exactly be a pleasant experience.
There’s no record of cookiecutters killing people but they have tasted human flesh before. In 2017, one swam through a swimming enclosure on Magnetic Island and bit a seven-year-old on the leg.
Rummer said cookiecutters were opportunistic feeders with limited vision that will have a go at anything they comes across. They can cause larger animals problems by leaving them with open wounds.
“That’s an entry point for infection so the whale is also immune compromised as well,” Rummer said. “It would evoke an immune response in the whale and probably cause that whale to expend a lot of energy fighting off infection.”
So you don’t need to freak out when swimming at the beach. Just think of all those other bigger, more terrifying sharks instead.
Has this happened before?
Sometimes, yes. McPhee said cookiecutters are known to bite inanimate objects and have attempted to eat submarines and undersea cables.
National Geographic has reported cookiecutters caused some damage to a nuclear submarine, attacking “exposed soft areas including electrical cables and rubber sonar domes”. You’d hope that’s not a problem with Australia’s future submarine fleet for which the government is paying up to $368bn.
Rummer said the sharks likely mistook the catamaran for a large carcass. She said the sharks spend most of the day in deep waters and surface from dusk to dawn looking for “cookies”.
“If you can imagine, they’ve got limited vision and it’s dark. They see an inflatable catamaran with a big surface area that is soft and flat. ‘Is it a whale? Let’s have a look. Oh, yep, that tastes like rubber. It’s not for me.’
“The other aspect is this species does often travel in schools and if they’re all going at this inflatable thinking it’s a potential food item, that’s where you damage as there are multiple bites.”
