This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Researcher Eugenie Clark is 90 years old. Her office shelves are lined with gaping shark jaws. One is from a tiger shark. It bit her once—the only shark bite of her life.
She was driving to talk to a student group, and the shark jaw sat on the passenger seat. She made a quick stop at a red light, and the jaw flew forward. Clark shot her arm out to stop the teeth from hitting the dashboard.
“Instead, it cut my arm,” said Clark.
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After years of swimming with live sharks, that’s the closest Clark’s come to meeting Jaws.
“I’ve had sharks come up to me, I’ve even pushed a shark away,” Clark said. “I’m not easily frightened.”
Sharks are curious, Clark is curious. They’re a good match.
Clark is an ichthyologist and shark behavior researcher. Over the years, she’s opened her own marine laboratory and discovered the unexpected about many species of fish. She is a member of the National Geographic Society and has carried the flag of the Explorer’s Club and the Society of Women Geographers on dives around the world. Today, Clark is Senior Scientist and Director Emeritus at the Mote Marine Laboratory.
Some know her as “The Shark Lady.”
One of the first sharks Clark ever caught was a lemon shark. Despite the cute name, the lemon shark is spooky. Its pale grey skin blends in with sand in shallow water. Its yellow, cat-like eyes scan for squid and rays.
In the late 1950’s, after creating the Cape Haze Marine Laboratory (later renamed the Mote Marine Laboratory), Clark and her colleagues caught a group of lemon sharks as part of a plan to study the low incidence of cancer growth in sharks. After taking care of the sharks for several weeks, a lab assistant started wondering if the lemon sharks were watching them back—even learning.
From inside the tank, the sharks seemed to react to whether the scientists were carrying a food bucket. It seems simple; after all, even a shih tzu knows when it’s dinnertime. But many researchers back then didn’t think of sharks as animals that could learn.
“People thought they were just dumb eating machines,” said Clark. “We started testing their intelligence. They don’t have much expression on their faces, but they know a lot of what’s going on.”
In 1956, Clark and her colleagues started a series of experiments where they taught lemon sharks to press buttons and learn sequences. They published this research in Science in 1958. Later studies showed that many other shark species learn from their environments.
Another surprise came when Clark started talking with local fisherman during a diving trip near the Yucatan Peninsula. The fishermen told her stories of underwater caves where huge sharks lay sleeping. Clark decided to investigate.
The fishermen spoke the truth. Clark found submerged caves where live reef sharks lay motionless, watching the world through lidless eyes.
“They’ll follow you with their eyes as you move around the cave,” said Clark. “They can stay that way for hours.”
What many might think is creepy, Clark sees as a key to understanding shark behavior and how they interact with the environment. Clark’s visit to the “Cave of the Sleeping Sharks” led to several articles for National Geographic, including a photo of Clark on the cover of National Geographic in April of 1975. In the photo, Clark swims next to the mouth of a large bull shark, her hand grips its dorsal fin.
Clark said understanding shark behavior is important if researchers want to protect sharks from humans. She said people don’t realize that sharks eat the sick fish in reefs. By eliminating sick fish, sharks protect other fish from pathogens. Without sharks, disease could spread and the whole reef could suffer.
Clark has gone on diving expeditions on reefs around the world, and she knows there are still mysteries out there. Just last year, Clark was one of the first scientists to describe the shark species Cephaloscyllium stevensi, which lives off the coast of Papua New Guinea. This shark is called a swellshark because it can gulp down water or air and puff up, blowfish-style.
Clark said no one knows exactly why a shark needs to swell up. Unlike blowfish, swellsharks are the predators, not the prey. Clark thinks the sharks might swell up so they can wedge themselves in small caves. Keyword: might.
“The swell shark is mainly in deeper water, and no one has really studied them in their natural habitat,” said Clark.
Some day, a researcher like Clark will swim close enough for answers.
“People really are hungry for knowledge about the sea,” said Clark.
“I watched sharks in an aquarium when I was nine years old, and I thought they were wonderful.”