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The cookiecutter shark gained fame through its appearance in the 2011 horror movie Shark Night 3D, yet much about this elusive predator remains unknown. Here are some intriguing details we’ve uncovered.
1. This shark has undergone three scientific name changes: Initially named Tristius brasiliensis in 1824, it was later reclassified as Scymnus brasiliensis, and finally settled as Isistius brasiliensis. The genus name honors Isis, the Egyptian deity of light, while the species name highlights its presence off Brazil’s coast.
2. Its name derives from the cookie-shaped bites it leaves on its prey, earning it nicknames like the cigar shark. For multilingual enthusiasts, the Florida Museum of Natural History offers alternatives: almindelig cookiecutterhaj (Danish), cação luminoso (Portuguese), kleiner leuchthai (German), koekjessnijder (Dutch), squalelet féroce (French), and tiburón cigarro (Spanish).
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3. The term 'cookiecutter' is a bit deceptive—the shark’s bites are actually cone-shaped. (As Ed Yong from National Geographic points out, 'ice cream scoop shark' might be a more fitting name.)
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4. The cookiecutter shark’s underside glows due to photophores, light-emitting organs in its skin. Researchers believe this bioluminescence helps it blend with moonlight, while a dark, non-glowing collar around its throat mimics a fish, luring prey upward. (The shark can also flash these organs like a strobe light.) George Burgess, a shark expert at the Florida Museum of Natural History, told Wired that the collar does glow, potentially attracting predators to the shark’s mouth. Regardless of the lure, once prey is close, the cookiecutter strikes and secures its meal.
5. During the day, this shark resides at depths of 3200 feet, but it ascends vertically at night to hunt for food.
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6. When it comes to feeding, the shark employs its suction-like lips to latch onto prey. After attaching itself, the cookiecutter rotates its body, using the serrated teeth on its lower jaw to carve out a chunk of flesh—creating a crater-shaped wound measuring 2 inches wide and 2.5 inches deep—resulting in a ready-made meal.
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7. These sharks often prey on animals much larger than themselves, including tuna, stingrays, other sharks (even great whites!), seals, whales, dolphins, and more.
8. Humans have also fallen victim to their bites. There have been a few instances where cookiecutter sharks have fed on bodies in the water, and one long-distance swimmer, Mike Spaulding, was bitten by a cookiecutter during a night swim off Hawaii’s coast. Spaulding later shared the details of the encounter with Deep Sea News:
I was swimming under ideal conditions when the wind picked up slightly, and I hoped it was a temporary local change. We were on a 30-minute feeding schedule. At 8:15, I was about 80 to 100 yards behind the boat. The captain preferred to move ahead, then idle and wait for me to catch up. During the last stop, he mentioned difficulty seeing the kayak and suggested turning on our emergency light for better visibility. He also switched on his cabin lights. Fifteen minutes after the lights were on and I had my feeding, I began feeling soft bumps against me, which I assumed were squid. I didn’t like this sensation... After the fourth bump, I felt a sharp pain just left of my sternum. It was agonizing, and I cried out. Realizing the danger, I knew I had to exit the water immediately, ending the swim. I reached the kayak, turned off the light, and started climbing into the one-person kayak. As I prepared to push off, I felt a hit on my left calf. Running my finger over the area, I discovered a 2.5” by 0.75” hole where I’d been bitten. … The lights had attracted squid, which in turn drew the cookiecutter shark into the food chain.
Despite what Shark Night 3D might suggest, these sharks pose no real threat to humans.
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9. The shark sheds its entire lower row of 25 to 31 triangular teeth at once, then consumes them, likely for their calcium content. Additionally, cookiecutters have 30 to 37 small teeth on their upper jaw.
JSUBiology
10. The shark was first identified in the 1800s, but its role in creating distinctive marks on other sharks wasn’t understood until the 1970s. As Yong explains, “The initial breakthrough occurred in 1963 when Donald Strasburg observed that the cookiecutter shark sheds its saw-like lower teeth as a single unit. … In 1971, Everet Jones found small conical flesh plugs in the stomachs of these sharks. He also noted their mobile tongues and large lips enable them to create a vacuum on smooth surfaces. It became evident that this small creature was injuring some of the ocean’s largest inhabitants.”
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11. Even inanimate objects aren’t safe from cookiecutter sharks: In the 1970s, they posed a threat to nuclear submarines. The sharks bit chunks out of the neoprene-covered sonar domes of several U.S. submarines, causing oil leaks and rendering the systems ineffective. The solution was to cover the domes with fiberglass. Additionally, telecommunications and oceanographic research equipment have also been damaged by these sharks.
12. The cookiecutter shark is relatively small, with males reaching up to 16.5 inches and females growing to 22 inches in length.
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13. Cookiecutters are viviparous, meaning their young develop inside egg sacs within the shark’s uterus. The mother gives birth soon after the baby sharks hatch from their egg cases.
14. It’s said that a cookiecutter shark’s photophores can continue glowing for up to three hours after death. Spooky!
