10 Interesting Facts About Cookiecutter Sharks!

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Cookie Cutter Shark teeth
Cookie Cutter Shark's teeth. Image credit: JSUBiology cc2.0

10 Interesting Facts About Cookiecutter Sharks!

Cookie Cutter Shark teeth
Cookie Cutter Shark’s teeth. Image credit: JSUBiology cc2.0

When you hear of an animal with a weird name, it’s only natural to be curious, and when it comes to sharks, no shark probably has a weirder name than the cookiecutter shark. Does this animal really exist? What kind of animal is it and how did it get its weird name? Let’s find out.


1. There are two known species of cookiecutter sharks.

Cookie_cutter_shark_Isistius_brasiliensis_distmap
Distribution map for the Cookiecutter shark. Image credit: Chris_huh GFDL

There is the smalltooth cookiecutter shark or smooth cookiecutter shark, also simply known as the cookiecutter shark and the largetooth cookiecutter shark. They are the same size and look roughly the same with their mouths closed, except for the fact that the cookiecutter shark has a dark ‘collar’ around its gills. With their jaws gaping open, it is easy to tell both species apart – the largetooth cookiecutter shark has much larger lower teeth than its cousin.

The cookiecutter shark is common, found in waters all over the world to as far south as New Zealand and as far north as Japan, commonly found around islands. The largetooth cookiecutter shark is rarer. In fact, only ten of them have ever been caught – off the coasts of southern United States, Brazil, North Africa, Japan and Australia. Scientists believe that this is because the largetooth cookiecutter shark prefers deeper waters.




2. They are named after an Egyptian goddess.

Ägyptischer_Maler_um_1360_v._Chr._001
Isis depicted with outstretched wings (wall painting, c. 1360 BCE). PD Image

The cookiecutter shark and the largetooth cookiecutter shark belong to the genus Isistius. The scientific name of the cookiecutter shark is Isistius brasiliensis while the scientific name of the largetooth cookiecutter shark is Isistius plutodus.

The word Isistius comes from the name of Isis, the Egyptian goddess of the throne, of nature, of magic, of mothers and of children. She was also known as the goddess of heavenly lights, which was why cookiecutter sharks were named after her.

You see, cookiecutter sharks are bioluminescent. What this means is that it is one of the few living organisms that can produce its own light, just like fireflies. Indeed, cookiecutter sharks may appear brownish, pinkish or grayish in color but in the dark, they produce a bright green glow, thanks to the light-producing cells called ‘photospores’ that cover their underside. They are bright on the bottom so that they don’t really look like fish to would-be predators while they are dark on top to hide themselves from potential prey.

The second part of the smalltooth cookiecutter shark’s scientific name, brasiliensis, comes from the fact that it is frequently seen around Brazil while the second part of the largetooth cookiecutter shark’s scientific name, plutodus, comes from two Greek words – plutos meaning ‘great’ and odous meaning ‘teeth’.


3. They are also known as cigar sharks.

Isistius_brasiliensis_cigar_shark
The dark collar band of the cookiecutter shark. PD Image by PIRO-NOAA Observer Program

Cookiecutter sharks are known by another weird name – cigar sharks. This is because they have long bodies and rounded heads, much like cigars. The smalltooth cookiecutter shark, in particular, looks like a cigar because of the dark band around its gills.

Aside from their cigar-shaped bodies, cookiecutter sharks have large green eyes located near the front of their heads, which scientists believe give them good enough vision, but not binocular vision. They also have small nostrils that are covered with flaps of skin and three fins near the tail. Their largest fin, the caudal fin, can give them a burst of speed so that they can catch up to their larger prey.


4. They have the largest teeth of all sharks.

Now, you might find this hard to believe, but it’s true. Cookiecutter sharks have the largest teeth among all sharks, even larger than the teeth of the fearsome great white, that is, in proportion to their bodies. This means cookiecutter sharks are small but they have big teeth.

Cookiecutter sharks have about 60 to 70 teeth all in all, with more teeth on the upper jaw and fewer but larger and broader teeth on the lower jaw. The shape of the teeth are also different. The upper teeth are narrow and straight like needles while the lower ones look like fence tips, straight and then pointed. All of the cookiecutter shark’s teeth have straight edges, unlike the teeth of the great white shark, the tiger shark and many other sharks, which have jagged edges like the blade of a saw.

Cookie Cutter Shark teeth
Cookie Cutter Shark’s teeth. Image credit: JSUBiology cc2.0

5. …Which they use to take chunks out of larger fishes…

So why is the cookiecutter shark named so? The answer lies in the way this shark eats.

During the day, cookiecutter sharks lie in the depths of the ocean but at night, they come close to the surface to feed. They look for larger fish like tunas, stingrays and larger sharks, even great white sharks, or marine mammals like dolphins, whales, dugongs and seals, then they swim to it and take a huge bite with their sharp teeth.

It’s not just any bite, though. First, the cookiecutter shark attaches itself to its prey using its thick lips which act like a suction cup. Then, it sinks its upper teeth in to anchor itself. Finally, it sinks its lower teeth to slice the flesh while rotating its body, completing a circular cut, much like the cut on the dough left by a round cookie cutter. Not all cookie cutters are round, though, which is why some scientists suggest changing the shark’s name to ice cream scoop shark. Now, that would be more interesting, wouldn’t it?

Once done, the shark detaches itself and eats the chunk of flesh and if it’s still hungry, it goes for another bite, the process beginning all over again.

The prey of the cookiecutter sharks do not die directly from the bites but they can become weaker, which makes it easier for real predators to eat them. They can also get an infection and slowly die.

Aside from biting larger sea creatures, cookiecutter sharks also eat small squid and some small fishes whole to supplement their prey.

6. …And submarines…

Living sea creatures are not the only victims of cookiecutter sharks. Their teeth are so sharp and so strong they have even taken chunks off submarines, damaging sonar, telecommunications and research equipment. In the 1980s, roughly thirty submarines were damaged by cookiecutter sharks and since then, submarines have been coated with fiberglass to protect them.

7. …And humans.

We humans aren’t safe from cookiecutter sharks, either. Although no one has ever died from an attack from a cookiecutter shark, many have been bitten and you can bet those bites hurt. This is especially true in the case of shipwreck survivors, since most shipwrecks occur at night and in deep water. Sometimes, bodies that are recovered from shipwrecks show wounds caused by cookiecutter sharks.


8. They lose teeth in rows.

Cookiecutter_shark_teeth
The suctorial lips and large lower teeth of the cookiecutter sharks are adaptations for its parasitic lifestyle. PD Image by Karsten Hartel

With all the biting cookiecutter sharks do, it makes you wonder – don’t they ever lose their teeth?

Well, of course, they do. Cookiecutter sharks lose their teeth just like all other sharks. Remember, sharks lose teeth easily because they do not have bones, just tough cartilage. However, whereas most sharks lose their teeth one at a time and grow them back one at a time, cookiecutter sharks lose their lower teeth in rows. The teeth are all connected at the base so if one is damaged, the whole row is lost and a new one grows in place. Even if the teeth don’t get damaged, cookiecutter sharks still shed their teeth as they grow – at least 15 times before they reach their full size.

What happens to the old row of teeth? The shark swallows it, recycling the calcium.


9. They are among the smallest sharks.

By the way we’ve been discussing how fierce cookiecutter sharks are, you might think they’re quite large, but they’re not. Cookiecutter sharks grow 14 to 16 inches long on average – dwarves compared to the great white shark, which can grow over 20 feet long. The maximum size is 17 inches for males and 22 inches for females.




10. They can have as many as 12 pups.

Cookiecutter sharks, like many sharks, are ovoviviparous. This means that the young are nourished inside eggs in the female’s body, instead of in placental sacs. They are sustained by the yolk of the egg since they do not receive nourishment from their mother in any way. Once they are fully developed, the eggs hatch and shortly after, the female gives birth to the live young called pups. A female cookiecutter shark can have 6 to 12 pups in one litter, which measure five to six inches long at birth. Like with other sharks, mothers do not provide any care for their pups. Rather, it is entirely up to them to feed and survive.


Cookiecutter Shark Videos

The YouTube video below contains a playlist of 3 videos about cookie cutter sharks. The list of videos featured is underneath.

These videos are mentioned in the following books:
Sharks Early Readers
25 most Awesome Sharks
The Daily Shark

The Playlist:

  1. BBC: Perfect Shark – Cookie Cutter Shark. With the help of a shark expert and a room built with CGI, take a look at this deadly shark species, the Cookie Cutter Shark. With ambush as its main weapon of attack, could this be the world’s most Perfect Shark?
  2. Cookie Cutter Shark Bite on Dolphin by dolphincommproject. An Indo-Pacific Bottlenose dolphin swims by with a wound caused by a cookie cutter shark.
  3. Cookie Cutter Shark Big Island Hawaii Blackwater night dive by Big Island Divers. Extremely rare cookie cutter shark off Kona Hawaii.

More Shark Video Pages to Enjoy:
Tiger Sharks, Bull Sharks, Hammerhead, Mako, Great White, Megamouth, Goblin Sharks, Shark Senses, Sharks and Humans, Tonic Immobility, Whale Sharks, Lanternshark, Megalodon, Cookiecutter, Frilled Sharks, Spiny Dogfish, Basking Sharks, Angel Shark, Horn Sharks, Wobbegong, Zebra Shark, Blue Sharks, Nurse Sharks, Reef Sharks, Sand Tiger Shark, Oceanic Whitetip.


Sources:

http://www.sharksider.com/cookiecutter-shark/
http://en.wikipedia.org/wiki/Cookiecutter_shark
http://en.wikipedia.org/wiki/Largetooth_cookiecutter_shark
http://www.fishesofaustralia.net.au/home/species/3511#moreinfo

To view the complete list of sources, click here…

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