Researchers at James Cook University (JCU) in Australia were astounded when they saw a tiger shark throw up something totally unexpected.
They had been tagging the sharks off the coast of Queensland’s Orpheus Island in May 2022 when a shark vomited up a dead echidna. The team believe this discovery is a world-first.
“When it spat it out, I looked at it and remarked ‘What the hell is that?’” says former JCU PhD student Nicolas Lubitz. “Someone said to take a picture, so I scrambled to get my phone.”
Lubitz was able to take one photo, which shows the shape of the echidna in the water next to the three-metre-long shark. “We were quite shocked at what we saw. We really didn’t know what was going on,” he says.
Tiger sharks are known for eating pretty much anything – they’re often nicknamed ‘the trash cans of the sea’ and have even been found with tyres and license plates in their stomachs. “I’ve seen videos of them eating a rock for no reason,” Lubitz says.
Still, seeing the predator regurgitate an echidna, spines and all, was a total head-scratcher. “It was a fully intact echidna with all its spines and its legs,” he says.
Echidnas are an egg-laying mammal native to Australia. They look a bit like a hedgehog that told too many lies until its nose grew, like Pinocchio.
The echidna was still whole when the shark threw it up so the researchers believe it was a recent kill.
Exactly how the shark managed to catch it isn’t entirely clear but Lubitz assumes that the tiger shark could have taken the echidna while it was swimming in the shallows or between the islands (fun fact: although they live on land, echidnas can swim – paddling with their feet and using their long nose like a snorkel).
Sharks don’t often throw up their food but it does happen. They sometimes regurgitate what they’ve eaten when they’re stressed, says Lubitz: “In this case, I think the echidna must have just felt a bit funny in its throat."
The tiger shark was unharmed by its dodgy meal and the researchers were able to fit the animal with an acoustic tag to help them track its movements. The species is critically endangered so learning more about them is a vital part of protecting them from extinction.
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