December 5, 2013
Sharks Prefer To Attack Prey From Behind
Brett Smith for redOrbit.com - Your Universe Online
As if the razor-sharp teeth, powerful jaws and lightning-quick speed weren’t enough, a pair of marine biologists have now found that sharks prefer to attack from behind, according to a new study in the journal Animal Cognition.
Previous research has shown that many predators, including sharks, attempt to perceive the body shape, size and movement of their potential prey. Marine biologists have also found that sharks prefer to operate outside the field of vision of their potential prey. These previous findings led the study team to theorize that sharks can identify human body orientation and can use this information to their advantage.
In the study, the researchers recorded the actions of Caribbean reef sharks when they were presented with a diver in full scuba gear in a kneeling position, looking forward on the sea floor. Next, the sharks were presented with two divers kneeling back-to-back to eliminate any blind spots.
The marine biologists chose Caribbean reef sharks because the animals frequently interact with divers in the Bahamas and are not considered to be a dangerous species for humans.
The study team discovered that more sharks approaching a single test-subject preferred to swim outside the diver’s inferred field of vision. The result suggested that sharks are capable of identifying human body orientation. However, the mechanisms behind the sharks’ approach remain unclear, the researchers said.
“Our discovery that a shark can differentiate between the field of vision and non-field of vision of a human being, or comprehend human body orientation, raises intriguing questions not only about shark behavior, but also about the mental capacity of sharks,” wrote study author Erich Ritter of the Shark Research Institute in a press release.
“The more research is conducted on how sharks sense and interpret humans, the better we will understand how to cope with them in their habitat,” added co-author Raid Amin of the University of West Florida.
Sharks have a reputation for being blood-thirsty man-eaters that ravage beaches around the world. But according to Time writer Bryan Walsh – the news media are more likely to enter a feeding frenzy that your typical shark.
“You’re not likely to see national news networks cover the 10 or so Americans who die from unintentional drowning each day with the same alacrity that they’ll flock to a fatal shark bite,” Walsh wrote earlier this week. “But chances are that the increase in shark attacks in Hawaii over the past couple of years is just a matter of chance.”
Walsh goes on to say that sharks should be much more afraid of humans than we are of them.
“Each year, fishermen kill as many as 73 million sharks, often cutting off their fins — for use in shark-fin soup, a popular dish in much of Asia,” he wrote. “And tens of millions more sharks die accidentally each year because of fishing gear set for other species.”
Earlier this year, the Discovery Channel was criticized for feeding into the sensational coverage of these marine predators by airing a fake documentary about the massive extinct shark Megalodon that suggested the animal may still lurk deep in the ocean.