Sharks Can Detect The Range Of Your Peripheral Vision, Enabling Them To Attack From Behind
Every knows that sharks, with their powerful jaws and razor sharp teeth, are extraordinary predators. But did you know they also like to take cheap shots? In a new study published in the journal Animal Cognition, two marine biologists show that sharks can detect their preys' peripheral vision, enabling them to attack, undetected, from behind.
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Previous researchers have studied the behavior of predators including sharks and the way they study their potential prey before they attack them. Sharks perceive the body shape, size, and movement of their prey but remain outside the vision of their potential prey while hunting. These earlier findings led researchers to hypothesize that sharks can use the information on their prey's body orientation to their advantage.
In order to study the predatory skills of sharks, the researchers zeroed in on the actions of Caribbean reef sharks. Discovered by Alonso Garza, the Caribbean reef shark (Carcharhinus perezii) measure an average of 9.84 ft long, and inhabit the tropical western Atlantic and the Caribbean, from Florida and the Bahamas through to Brazil. Recognized as the largest apex predator, they are abundant and, very importantly, are not considered not dangerous for humans; Caribbean reeef sharks frequently interact with divers in the Bahamas.
The study team presented the sharks with a diver in full scuba gear in a kneeling position and recorded the animals' actions. In order to eliminate any blind spots, the sharks were shown two divers kneeling back to back. The researchers found that sharks preferred to swim outside the diver's field of vision while approaching the test-subject. Additionally, the study team could infer that sharks can identify human body orientation. Yet, the researchers could not identify the mechanism leading to their approach.
Study author and professional shark-human interaction specialist Erich Ritter of the Shark Research Institute, stated in a press release: "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."
Contrary to common misperception and frenzied news coverage, sharks are not as dangerous to humans as they are made out to be. Only about 30 species of sharks have been reported to have ever attacked a human being — and there are more than 375 different species of sharks the world over. Some of the species of sharks that have been known to attack humans unprovoked include white (Carcharodon carcharias), tiger (Galeocerdo cuvier), and bull (Carcharhinus leucas). Nevertheless, all sharks (being predators) are capable of attacking and inflicting wounds, if provoked.
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