Naked Science Forum
Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: CaptMoldman on 17/12/2015 18:19:21
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I just read this article about the cookie-cutter shark that regards it almost comically for its diminutive size. Obviously, human interaction with the cookie-cutter shark is far from frequent, but if such interactions were actually common, how likely is it that a single cookie-cutter shark could actually inflict mortal damage on a swimmer? (Just to clarify, I abhor any mistreatment of sharks and only ask this as a curiosity since I found the tone of the article dismissive of what I would regard as significant damage).
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I've never seen a cookie-cutter shark - have you got any images of them?
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Here you go: (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.ourbreathingplanet.com%2Fwp-content%2Fuploads%2F2014%2F09%2F1.png&hash=773838cfc56e4cb027dd047bcf2f172a)
Maximum length recorded is 56 centimeters so they aren't large, but their "cookie-cutter" jaws seem to be able to really cause some damage.
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Wow - they're real "lookers" aren't they?! Where do they live? And what do they do with that impressive array of teeth? They look llike they might use them for scraping things off rocks?
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They're actually located pretty deep but have been known to use those teeth to cut holes into submarines. There's only been one reported attack on a human when one took two chunks out of a training swimmer. He was okay but I can't imagine the wounds were insubstantial.
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So what do they eat?
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They eat other fish. People have found dead fish with perfectly circular wounds in them and it's credited to the cookie-cutter shark.
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As you wrote, Capt., the cc shark is a deep dweller. By day (if memory serves me well) below 3kms. At night the 40 - 55cm long cc shark comes nearer to the surface to feed. Its underside is bioluminescent so it does not cast a shadow in the moonlit water which might attract predators. However it has a black collar which, from below it, gives the appearance of a small fish which would make a tasty morsel for sharks, dolphins, tuna etc. Being close to the cc shark's mouth, an inquisitive predator discovers its mistake too late and the cc shark quickly attaches itself to the would-be predator, thus the predator becomes the prey.
The cc shark's lips, which are well illustrated in your photo, act as a mobile sucker and enable the forward facing saw like teeth to bore out a conical lump of flesh. Being so well attached to their prey, there is little chance of the poor old predator-come-prey turning the tables again to revert to being the predator once more. Once it has its lump of food cut out, the cc shark detaches from the prey and beats a hasty retreat, leaving the wounded prey nursing a hole in its side. This hole might be around 5cms in diameter and 7cms deep.
So, could this shark inflict a mortal wound on a human? A 5 x 7cm hole would undoubtedly result in heavy blood loss, not to mention be excruciatingly painful, perhaps to the point of causing loss of consciousness. So I would say such an attack would be life threatening. But would a cc shark attack a human?
Given that cc shark wounds have been found in large fish such as tuna, marlin and other sharks, including the great white, and in dolphin, a human might just be within the cc shark's prey size range. But, as mentioned above, they dwell way beyond the depths of even the most adventurous scuba divers, around 10 x deeper, and only come within range of humans at night, when most swimmers and divers are back on terra firma. The only cc shark wound found on a human, that I am aware of, was in the sea off Japan. But even here, a PM established that the body was already dead in the water when the attack occurred.
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And back then I thought hagfishes were scary...