He says that could explain why the tiny blue shark dominated a mature mako-it had a lot of gumption, while the mako may have been more reserved. To Elliott, the most "ground-breaking" part of his experiment was observing what he calls Jane Goodall theory-the idea that animals' behavior is based on their own life experiences and personalities. "Sharks could feed from different parts of the whale carcass without having to come together." 'Jane Goodall Theory' ( Also read about how sharks 'shrug their shoulders' to swallow food.) "They might be the best proxy we have for behaviors that might be seen in response to a drifting food source, such as a whale carcass, but by the same token, a large drifting whale carcass does not force the animals to have to compete for the same resource, in the way that some fish carcasses on the end of a rope would do," says Anderson, who is also a National Geographic Society grantee. There's a caveat: Behaviors seen in a baited situation are not necessarily natural, he adds. "So gaining a better understanding of the dynamics of social relationships between species is interesting and novel," Anderson says by email. James Anderson, a biologist at the University of Hawaii at Mānoa, noted that documenting such interspecies interactions is difficult-most studies that have examined shark behavior in baited situations deal with only one species. ( Read how sharks can find their way home in the vast ocean.) They cut tuna into meter-cubed "ice pops" and chummed a half-mile trail over five days to lure sharks into the vicinity. It's near a seamount that Elliott-a National Geographic Society grantee-and his team set up their experiment. It's relatively low in life-forms with the exception of food-rich oases such as continental shelves and volcanic seamounts. The open ocean is often called a blue desert. As the most exploited shark in the world-mostly for its fins-the blue is also one of the least studied, something Elliott is trying to change. They put down their swords because they see that food is available," says Elliott. "We basically observed these animals throwing caution to the wind. While filming a new episode for Nat Geo WILD's SharkFest, Elliott traveled off the coast of New Zealand into the remote southwestern Pacific with a specific plan: To simulate a rare feeding event in the open ocean and observe how blue sharks and shortfin makos-both open-water sharks that tend to stick to their own kind-interact when forced into close proximity. But Elliott's observation seems to upend that. Shark experts have always believed there's a clear hierarchy in how sharks interact with one another-namely, that size matters. "What we saw broke a lot of theory in shark behavioral biology that size is the trump card," says Elliott, of the University of Auckland in New Zealand. ( Explore a stunning interactive of the "lords of the sea.") The bigger fish obliged, allowing the blue to eat in peace. At possibly 15 feet long, she is the biggest shortfin mako Riley Elliott has ever seen: "We were just struck with awe."īut it's what happened next that really floored the marine scientist.Ī blue shark ten times smaller darted onto the scene and aggressively pushed the mako-the ocean's fastest shark-away. Thick as a torpedo and heavily scarred, the gigantic shark rises from the deep, circling the bait near the surface.
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