All About Sharks
Inside The Mind Of A Shark
Most of us think of sharks as mindless killing machines, but are they? Shark experts have been finding clues that point to a complex social life and a surprising level of intelligence among sharks.
Shark intelligence is difficult to measure. We can’t give sharks an IQ test or probe them with questions. We can only get a glimpse into their minds by observing their behavior. Here are five reasons why scientists think sharks learn and problem solve rather than simply coasting by on pure instinct.
Great white sharks have learned to use different hunting strategies for different prey. At Mexico’s Guadalupe Island, white sharks have learned to attack giant elephant seals from the rear to avoid their sharp canines, and to retreat while their prey bleeds out to avoid a struggle. But when attacking smaller harbor seals, they simply pluck them from the surface and drag them down until they suffocate.
Great whites aren’t born knowing how to hunt seals. They have to learn. At South Africa’s Dyer Island, young great whites are often seen clumsily attacking their prey, and usually missing. After years of practice, they eventually “graduate” to hunting at nearby Seal Island, where old veterans like Colossus have a 48% success rate when attacking seals at the surface. Sharks don’t give up; they learn through trial and error.
Competition for prey can be fierce, so white sharks have worked out a clever social ranking system to avoid costly fighting. Specific behaviors like circling, fin flapping and tail thrashing are some of the ways that white sharks have learned to establish dominance or contest kills without resorting to violence.
Sharks are curious creatures. They commonly approach divers and boats to investigate in a non-threatening way. Sharks mouth or take test bites of potential prey to get a better sense of what they are; in fact, most sharks attacks are simply test bites. Sharks may also play; porbeagles seemingly playing with kelp and driftwood, and great whites have been observed tossing live seals repeatedly into the air.
While we think of sharks as solitary creatures, they do occasionally band together. Sevengill sharks work together to encircle their prey; one will play decoy while another attacks from behind. Whale biologist Peter Best reported seeing a group of white sharks working together to move the carcass of a beached whale into deeper water so that they could more easily feed on it, suggesting they also understand the basics of flotation.
Aquarists at the Shedd Aquarium in Chicago conditioned sharks over a ten-year period to respond in specific ways to specific cues, proving that sharks can be trained just like whales and dolphins. More Videos
A Guide to Understanding Shark Body Language
Instead of engaging in potentially deadly combat, great white sharks have nonviolent ways of communicating, establishing dominance and venting their frustration. Researchers have documented several different types of great white social behavior.
Two sharks follow each other in a circle, possibly to identify each other or determine rank.
Two white sharks swim slowly side-by-side to compare size and establish rank. The submissive shark swims away.
One shark stretches out in front of another, showing off its size. This is likely to establish dominance.
Two sharks swim closely by one another, likely to identify the other shark or size one another up in order to clarify rank.
A submissive shark will always turn and give way to the dominant shark, which stays its course.
One shark thrashes its tail at another to claim ownership of a kill. The shark that makes the biggest splash wins.
A shark arches its back in response to a threat before fleeing or attacking.
After failing to catch a seal decoy, white sharks have been seen gaping their jaws above the water’s surface – possibly as a way to get out their frustration.
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