Photo: Sharkdivers blogspot
A paper published in the June edition of Pacific Science details the "First documented attack on a live human by a cookiecutter shark". Pictured above, the cookiecutter shark uses large teeth fixed in its bottom jaw to bite out a cookie-cutter shaped piece of flesh from its victim. They might be better named "melonballer" sharks based on their suspected modus operandi:Scientists believe the cookiecutter shark suctions its jaw onto its target, and rotates about its axis to carve out a meal. However, this paper casts doubt on the melon-baller theory, noting that the victim felt pain only very briefly, and did not note any sensation suggesting the shark was rotating its mouth.
The paper documents an attack on long-distance swimmer Mike Spalding, who was bitten during an attempt to swim from from the Big Island to Maui across the Alenuihaha Channel. Apparently, the shark first tried to take a snack from the swimmer's chest, but found the pickings slim. As the swimmer was attempting to board a support kayak, the shark found better purchase in his fleshy lower leg. Mike was treated quickly in hospital and recovered well from the attack.
Human interactions with cookiecutter sharks are rare, perhaps partly because they feed at night when swimmers have left the water. Nonetheless, the authors of the study conclude: "Humans entering pelagic waters during twilight and nighttime hours in areas of Isistius sp. zoogeographical ranges should do so with a full appreciation that cookiecutter sharks may consider a human an appropriate prey item, especially when near man-made illumination, during periods of bright moonlight, or in the presence of bioluminescent organisms."
The cookiecutter shark makes itself useful to science in other ways: the characteristic bite can be easily identified on other migrating aquatic species, helping scientists to track their movement across territories inhabited by the cookiecutter sharks.
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