Tiny Shark Packs Big Bite

Few people have ever heard of the cookiecutter shark. They are prevalent in the deep, tropical ocean but they are not very large predators. In fact, the fish measures just a couple of feet long. But don’t be fooled by its size. This is a saw-toothed fish that bites dolphins, whales, nuclear submarine seals and now at least one person.

Maui man Mike Spalding becomes the first documented case of a human being bitten by the cookiecutter shark. He was swimming in deep water at night between the big island of Hawaii and Maui when he felt a pin prick in this chest followed by searing pain in his leg.

The tiny shark took a sizable chunk out of his calf muscle and the injury took months to heal. That was in 2009. Now several years later, scientists are taking a closer look at this small, ferocious shark.

The Florida Museum of Natural History houses a cookiecutter shark specimen but few people have ever heard of the species. the museum’s shark attack expert George Burgess says, “They have the biggest teeth of any shark in relation to the size of their jaws.”

As one of the co-authors of the new study that appears in the journal Pacific Science (PDF), Burgess wants people to know that humans entering deep ocean waters away from shore at twilight and nighttime hours should do so knowing that cookiecutter sharks are a potential danger, particularly during periods of strong moonlight, in areas of manmade illumination, or in the presence of bioluminescent organisms such as glowing squid.

Spalding’s attack happened around sunset during a 30-mile long distance swim. He says he began seeing the bright bioluminescence of squid before the shark attacked. These sharks hide among glowing squid because they have glowing spots on their skin. When a larger animal feeds on the squid, the shark goes in for a wounding bite.

Spalding was swimming through a group of cuttlefish when he was probably mistaken for a dolphin or whale.

The Monterey Bay Aquarium’s curator of field operations John O’Sullivan says, “These animals are very small and very aggressive in behavior. People say, ‘Thank God these things don’t get big.’” He’s been trying capture a live cookiecutter shark for several years because he is fascinated by the small shark’s interesting behavior. But he says it’s “turning out to be more difficult than our white shark program.”

The study was led by Randy Honebrink of the Hawaii Division of Aquatic Resources and co-authors include Robert Buch of the Florida Program for Shark Research at the Florida Museum and National Oceanic and Atmospheric Administration Fisheries Service, and physician Peter Galpin of Maui Memorial Hospital.