Why Sand Tiger Shark Devours Aquarium Mate (Video)

By Taylor Kubota, Live Science Contributor

Any sharks that want to enhance their reputation as fearsome predators should follow the lead of a sand tiger shark at the Coex Aquarium in Seoul, South Korea, that surprised aquarium goers by devouring a fellow shark — and taking nearly a day to finish the job.

A video of the shark gulping down its shocking mouthful made its way around the Internet. This sand tiger shark (not to be confused with a tiger shark) is an 8-year-old female, measuring 7.22 feet (2.2 meters) long, Reuters reported. The unfortunate object of her dinner was a smaller, banded hound shark; the 5-year-old male was just 3.9 feet (1.2 m) long, according to Reuters.

"It's unfortunate anytime you see something like that, regardless of what the circumstances are," said Chris Plante, assistant curator at the Aquarium of the Pacific, after viewing the video at Live Science's request. "But that's the law of animals, whether they're in the wild or not." [See Amazing Photos of Animals Gulping Down Their Prey]

While the size of the prey makes this incident noteworthy, he said, this kind of shark-on-shark violence isn't wholly unexpected.

Observers think the attack occurred Thursday evening, with videos from the time showing almost the entire male sticking out of the female's mouth. Twenty-one hours later, only the tip of the tail was visible.

After all this time and effort, the female will probably regurgitate part of her aquarium neighbor, said Jennifer Schmidt, associate professor of biological sciences at the University of Illinois at Chicago, told Live Science.

Plante wasn't at all shocked by the amount of time the shark had taken to eat this meal (Plante even thought it would take longer), but was surprised that it hadn't already regurgitated part of the smaller shark.

Experts and press from the aquarium all said the attack was likely a territorial dispute. Without having further details beyond the video, Plante and Schmidt agreed that the incident could have resulted from the smaller shark moving into the larger shark's space. Interactions such as these can occur in the wild, but the fact that these sharks were in captivity likely played a role. "Realize that these animals are in an extremely artificial environment. Sand tigers and hound sharks could overlap in the wild […] but the chance two animals would ever be in that close of a proximity in the wild is extremely small," Schmidt said. Sharks are predators, so this could have been a purely instinctual reaction to the hound shark swimming by, she said.

Attacks such as this one can also result from new sharks being added to tanks with others that are more established, Plante said.

Sand tiger sharks (Carcharias Taurus) have a distinctive, menacing appearance: They are bulky with jagged, irregular teeth lining a mouth that stretches past their eyes. "Some institutions actually call them ragged-tooth sharks because they have those nasty-looking teeth. But they're actually docile animals," said Schmidt. In addition to eating various kinds of fish, rays, squids and crustaceans, sand tigers are known to eat smaller sharks. The size of this banded hound shark, however, was much larger than what a sand tiger would usually consume, she said. [See Photos of a Sand Tiger Shark Nursery]

This display of predatory prowess is impressive, but sand tigers are not especially dangerous as far as sharks go. Between 1580 and 2014, the International Shark Attack File has a record of 29 unprovoked sand tiger shark attacks on humans. Plante said that in the field, sand tiger sharks do warrant the taking of some added precautions by humans, as they are known to be a little more aggressive than other species when provoked. He added that all this depends on the individual shark as well. For example, Plante said that the sand tiger shark at the Aquarium of the Pacific is relatively easygoing, but previous ones have been more aggressive.

As with all sharks, we are more dangerous to sand tiger sharks than they are to us. Sand tiger sharks are listed as "vulnerable" species on the International Union for Conservation of Nature Red List of Threatened Species. This species has a very low reproduction rate — females give birth to one or two pups every one or two years — so its population is easily threatened by human activity. In particular, commercial fishing, spearfishing and meshing used to keep sharks from swimming into populated beach areas have been problematic for sand tiger sharks.

On a less gruesome note, researchers from the Wildlife Conservation Society's New York Aquarium just reported the discovery of a sand tiger shark nursery in the Great South Bay, near Long Island's southern shore.

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