The cookiecutter is a cinematic star thanks to a supporting role in the 2011 horror film Shark Night 3D, but there’s a lot about this rarely-seen shark that’s still a mystery. Here are a few things we do know.
1. It’s had three scientific names: When the shark was discovered in 1824, it was named Tristius brasiliensis, followed by Scymnus brasiliensis, and, finally, its current name, Isistius brasiliensis. The genus name refers to Isis, the Egyptian god of light; the species name refers to one place it's found, off the coast of Brazil.
2. Its common name comes from the cookie cutter-like wounds it leaves in its prey. Its shape has also led some to call it the cigar shark. If you prefer to refer to it in another language, though, the Florida Museum of Natural History has you covered: almindelig cookiecutterhaj (Danish), cação luminoso (Portuguese), kleiner leuchthai (German), koekjessnijder (Dutch), squalelet féroce (French), and tiburón cigarro (Spanish) are just a few you could use.
3. The name cookiecutter is somewhat misleading—the shark’s bites are actually conical. (Ed Yong at National Geographic suggests that “ice cream scoop shark” might be more accurate.)
4. The entire underside of the cookiecutter glows thanks to light-emitting organs in its skin called photophores. Some scientists think the sharks use this bioluminescence to blend in with the moonlight, while a dark, unlit collar around its throat, which resembles a fish, draws its prey up from the bottom. (The sharks are also capable of using the organs to flash like a strobe light.) However, George Burgess, a shark expert at the Florida Museum of Natural History, told Wired that the collar does, in fact, glow, and “suggests that by flashing, the band may help draw would-be predators to the 'business end' of the shark.” Regardless of what’s luring the prey, once it’s close enough, the cookiecutter does a bait and switch and has a meal itself.
5. The fish lives at depths of 3200 feet during the day, but migrates vertically at night to feed.
6. Speaking of eating: To feed, the shark uses its suctorial lips to suction itself onto its prey. Once it’s attached, the cookiecutter spins its body, using the row of serrated teeth on its lower jaw to remove a plug of flesh—leaving behind a crater-like wound that is 2 inches across and 2.5 inches deep—and dinner is served.
7. The sharks typically feed on animals much larger than them, including tuna, stingrays, other sharks (even great whites!), seals, whales, dolphins, and more.
8. They’ve even bitten humans. There have been a couple of cases where the sharks have fed on bodies in the water, and one long distance swimmer, Mike Spaulding, was bitten by a cookiecutter while doing a night swim off the coast of Hawaii. Spaulding later described the circumstances behind the incident to Deep Sea News:
I was swimming along in perfect conditions. The wind kicked up a little and I was hoping that it was a local condition that would disappear. We were on 30 min[ute] feeding schedule. At 8:15 I was trailing the boat by about 80 to 100 yards. The boat captain liked to run ahead and then go out of gear and wait for me to catch up. On the previous feeding stop he complained about not being able to see the Kayak and requested we turn on our emergency light so he could see us better. He also turned on his cabin lights at the same time. Fifteen minutes after we turned on the lights and I had my feeding I started to feel squid bumping into me. I assumed they were squid as they felt soft. I did not like this at all ... After the 4th bump I felt a sharp prick just to the left of my sternum. It was excruciating and I gave a yelp. As soon as that happened I knew I had to get out of the water and the swim was over. I reached the front of the kayak and turned off the light and started climbing into a one person kayak. As I was about to push onto the kayak I felt a hit on my left calf. I ran my finger down my leg and felt a 2.5” by ¾ inch hole where I had been hit. … The lights attracted squid with in turn created a food chain which the cookie cutter shark was a part of.
Still, despite what Shark Night 3D would have had you believe, they’re not a danger to us.
9. The shark loses its bottom row of triangular teeth—25 to 31 of them—as a unit, then ingests them, probably for calcium. Cookiecutters also have 30 to 37 tiny teeth on the top jaw.
10. The shark was discovered in the 1800s, but no one knew it was responsible for the marks on other sharks until the 1970s. According to Yong, “The first breakthrough came in 1963, when a man called Donald Strasburg noticed that the cookie-cutter shark would shed its saw-like lower teeth as a single unit. … In 1971, Everet Jones discovered small conical plugs of flesh in the stomachs of these sharks. He also noticed that their mobile tongues and large lips allow them to form a vacuum on a smooth surface. It became clear that this tiny animal was wounding some of the ocean’s mightiest residents.”
11. Some inanimate objects also have something to fear from cookiecutter attacks: The shark posed a threat to nuclear submarines in the 1970s. Cookiecutters took chunks out of the neoprene-covered sonar domes of several American subs, which caused the sound-transmitting oil to leak and blinded the vehicles. To solve the problem, the domes were covered with fiberglass. Telecommunications and oceanographic research equipment have also been damaged by cookiecutters.
12. The shark is small: Males grow to a maximum of 16.5 inches, while females grow to 22 inches.
13. Cookiecutters give birth to live young that develop inside egg sacs in the shark’s uterus; the mother gives birth shortly after the baby cookiecutters hatch out of the egg cases.
14. Reportedly, a shark's photophores can emit a glow up to three hours after it dies. Creepy!