Sure, when blood hits the water, sharks know exactly where to go. But how do they hunt for less-obvious meals? New research says they use math.
How exactly the sharks move seems to vary with how much food is around.
Imagine yourself in a Walgreens, picking up a few necessities on your way home from work. You might make short movements, darting between aisles, crossing and recrossing your path as you debate between generic and name-brand. Apparently, sharks do the same thing when they have a lot of food in one area. Scientists even suggest their pattern is Brownian, no more intelligent than the aimless sway of microscopic particles buffeted by water molecules.
But in the vast expanses of a Walmart on a Saturday afternoon, your hunt might look a little different. After picking up a few items in one section of the store, you make a long traverse to another section, rolling your blue cart ahead of you. In food-sparse environments, the researchers argue that sharks also seem to make these long journeys. Here, the sharks appear to use Lévy flight search patterns, long suspected by mathematicians as the most effective way to hunt, but never before successfully traced to an animal’s actual search patterns.
The research team, including David W. Sims of the Marine Biological Association of the United Kingdom, used radio tags to study the hunting patterns of fourteen species of open-ocean predatory fish, including sharks, tuna, billfish, and ocean sunfish.
Though other studies have been quick to call animals’ motions Lévy-like, such as an investigation of albatross travels in 1996, previous scientists didn’t have enough data to fit the motion with the mathematical pattern. Sims’ team gathered more than 12 million data points over 5,700 days. He told Science News that this research is “the strongest evidence yet that these Lévy patterns are exhibited by wild animals.”
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