Coelacanth Hunt While Upside Down, According to Study

Researchers have recently increased their understanding of one of the world’s rarest fish. Using CT and MRI scanners, they were able to expose the physiology of a coelacanth (pronounced SEE-l-kanth) and found something surprising. The rare, endangered, deep-sea fish is designed to attack its prey while swimming upside down. Scientists call it “head drift hunting”.

“It’s quite unique,” Henrik Lauridsen, associate professor of the Department of Clinical Medicine at Aarhus University in Denmark, said in a press release. “The heaviest parts are on both ends of the fish, which makes it easy for the fish to stand on its head.”

Coelacanths have many bones in their heads and tails and minimal vertebrae, so they can swim vertically with their heads pointing toward the ocean floor while searching for food—usually cephalopods and small fish. They also lack a swim bladder. Fish usually live in caves more than 600 hundred feet deep. The lack of a swim bladder makes them less buoyant, so they don’t have to fight as hard to stay that deep.

Their preference for depth also keeps them well hidden from humans. A specimen netted in 1938 by a South African fisherman was thought to be the first sighting of an animal previously thought to have been extinct for 66 million years. Only about 300 more coelacanths have been caught worldwide since then. For the latest study, the researchers used a specimen that had been preserved for more than 60 years.

the fish going into the CT scan
The coelacanth specimen was captured in 1960. Henrik Lauridsen

“Instead of going out and capturing young coelacanths, which are rare and protected, modern scanning techniques have allowed us to perform exciting new analyzes despite the animal having been soaked in alcohol for decades.” , said Peter Rask Moller, University of Copenhagen. Professor and Curator of the Natural History Museum of Denmark. “Having museum collections of rare animals is like walking into the best thrift store in the world, with the wildest array of recycled stuff that can’t be found new anymore.”

Read further: Fisherman catches 90-million-year-old fossil in Missouri River

The entire, intact specimen currently being studied was caught in the Indian Ocean in 1960. It was donated to the Zoological Museum in Copenhagen, where it is on display whole and not cut. Other specimens have been dissected for research, but scientists still know relatively little about these creatures, which can grow to more than 6 feet long and weigh over 200 pounds.

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