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14 Facts About the Cookiecutter Shark

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Karsten Hartel / Wikimedia Commons

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.

Wikimedia Commons

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.) 

Wikimedia Commons

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.

Wikimedia Commons

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.

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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.

Wikimedia Commons

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.

JSUBiology

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.”

Wikimedia Commons

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.

Wikimedia Commons

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!

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Sylke Rohrlach, Wikimedia Commons // CC BY-SA 4.0
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Animals
Scientists Discover 'Octlantis,' a Bustling Octopus City
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Sylke Rohrlach, Wikimedia Commons // CC BY-SA 4.0

Octopuses are insanely talented: They’ve been observed building forts, playing games, and even walking on dry land. But one area where the cephalopods come up short is in the social department. At least that’s what marine biologists used to believe. Now a newly discovered underwater community, dubbed Octlantis, is prompting scientists to call their characterization of octopuses as loners into question.

As Quartz reports, the so-called octopus city is located in Jervis Bay off Australia’s east coast. The patch of seafloor is populated by as many as 15 gloomy octopuses, a.k.a. common Sydney octopuses (octopus tetricus). Previous observations of the creatures led scientists to think they were strictly solitary, not counting their yearly mating rituals. But in Octlantis, octopuses communicate by changing colors, evict each other from dens, and live side by side. In addition to interacting with their neighbors, the gloomy octopuses have helped build the infrastructure of the city itself. On top of the rock formation they call home, they’ve stored mounds of clam and scallop shells and shaped them into shelters.

There is one other known gloomy octopus community similar to this one, and it may help scientists understand how and why they form. The original site, called Octopolis, was discovered in the same bay in 2009. Unlike Octlantis, Octopolis was centered around a manmade object that had sunk to the seabed and provided dens for up to 16 octopuses at a time. The researchers studying it had assumed it was a freak occurrence. But this new city, built around a natural habitat, shows that gloomy octopuses in the area may be evolving to be more social.

If that's the case, it's unclear why such octo-cities are so uncommon. "Relative to the more typical solitary life, the costs and benefits of living in aggregations and investing in interactions remain to be documented," the researchers who discovered the group wrote in a paper published in Marine and Freshwater Behavior and Physiology [PDF].

It’s also possible that for the first time in history humans have the resources to see octopus villages that perhaps have always been bustling beneath the sea surface.

[h/t Quartz]

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This Just In
Criminal Gangs Are Smuggling Illegal Rhino Horns as Jewelry
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Valuable jewelry isn't always made from precious metals or gems. Wildlife smugglers in Africa are increasingly evading the law by disguising illegally harvested rhinoceros horns as wearable baubles and trinkets, according to a new study conducted by wildlife trade monitoring network TRAFFIC.

As BBC News reports, TRAFFIC analyzed 456 wildlife seizure records—recorded between 2010 and June 2017—to trace illegal rhino horn trade routes and identify smuggling methods. In a report, the organization noted that criminals have disguised rhino horns in the past using all kinds of creative methods, including covering the parts with aluminum foil, coating them in wax, or smearing them with toothpaste or shampoo to mask the scent of decay. But as recent seizures in South Africa suggest, Chinese trafficking networks within the nation are now concealing the coveted product by shaping horns into beads, disks, bangles, necklaces, and other objects, like bowls and cups. The protrusions are also ground into powder and stored in bags along with horn bits and shavings.

"It's very worrying," Julian Rademeyer, a project leader with TRAFFIC, told BBC News. "Because if someone's walking through the airport wearing a necklace made of rhino horn, who is going to stop them? Police are looking for a piece of horn and whole horns."

Rhino horn is a hot commodity in Asia. The keratin parts have traditionally been ground up and used to make medicines for illnesses like rheumatism or cancer, although there's no scientific evidence that these treatments work. And in recent years, horn objects have become status symbols among wealthy men in countries like Vietnam.

"A large number of people prefer the powder, but there are those who use it for lucky charms,” Melville Saayman, a professor at South Africa's North-West University who studies the rhino horn trade, told ABC News. “So they would like a piece of the horn."

According to TRAFFIC, at least 1249 rhino horns—together weighing more than five tons—were seized globally between 2010 and June 2017. The majority of these rhino horn shipments originated in southern Africa, with the greatest demand coming from Vietnam and China. The product is mostly smuggled by air, but routes change and shift depending on border controls and law enforcement resources.

Conservationists warn that this booming illegal trade has led to a precipitous decline in Africa's rhinoceros population: At least 7100 of the nation's rhinos have been killed over the past decade, according to one estimate, and only around 25,000 remain today. Meanwhile, Save the Rhino International, a UK-based conservation charity, told BBC News that if current poaching trends continue, rhinos could go extinct in the wild within the next 10 years.

[h/t BBC News]

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