Do sharks really attack submarines?
And the species that does so is a big surprise.
Cookie-cutter sharks were once known as cigar sharks, because nobody knew just how they ate. Once a biologist discovered their secret, it explained the mysterious deep holes made in the equipment of nuclear submarines.
Isistius brasiliensis isn’t scary. It’s only about a foot-and-a-half long and thinner than most adults’ wrists. There is one problem with it—it thinks nothing of attacking animals a lot larger than itself. Up until the 1960s, it didn’t occur to biologists to connect this innocuous-looking shark to the deep, crater-like bites that they saw in tuna, in dolphins, and in whales.
It wasn’t until 1971 that Everet Jones published a paper suggesting that the “cigar shark” was responsible for the “crater wounds” on fish and cetaceans. In 1969, Jones had been on an expedition during which he caught tuna with deep circular wounds. A day later, the expedition brought in more tuna, which shared a net with these small sharks. When Jones took a shark and placed it against the side of a fish, the shark bit into the fish, making a comparably-sized wound, but it was too weak to actually take out a chunk of flesh.
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