Great white sharks might be even more ravenous than previously thought. A new study shows that the world's largest predatory fish eat up to four times as much as scientists previously estimated.
Research from the University of Tasmania upends research done in the 1980s that stated that a 2000-pound great white could be sustained on 66 pounds of mammal blubber for as long as six weeks, perpetuating assumptions that the sharks could survive long periods without eating.
The great white shark, an apex marine predator, can grow up to 16 feet long and weigh as much as 5,000 pounds
The Australian research states that a white shark of that size could only survive for no more than 15 days on the same 66 pounds of mammal blubber.
"Our estimate of total daily energy expenditure suggests white sharks feed far more frequently than previously estimated and does not support the proposal that white sharks could survive at energy balance on [66 pounds] of marine mammal blubber for 1.5 months," the Australian report concluded.
The researchers tracked 12 great white sharks at Neptune Islands off the coast of southern Australia and calculated the shark's metabolic rate derived from swimming speeds, working out how much energy the sharks burned and how much food the sharks needed to survive.
Jayson Semmens, a senior researcher at the University of Tasmania and the study's lead author said the amount of energy required by the white sharks was equivalent to eating a seal pup every three days, the Japan Times reported.
He said the previous estimates on shark feeding done in the 1980s by U.S. researchers was probably skewed by a lazy shark.
"At the time it was a really novel study. They did some metabolic work similar to us but on [only] one shark. The white sharks at a seal colony where we worked, they're working pretty hard...They're coming up to some pretty high speeds to catch the seals. Their metabolic rate or the engine that runs them is much faster than what we had assumed," Semmens said to Australian ABC News. "These animals are probably going to be feeding, you know, every few days, rather than multiple weeks."
The research will help increase humans' understanding of the role sharks play in the marine ecosystem.
"We don't have a good handle on the population sizes of white sharks. We know that sharks in general are under pressure around the world from overfishing," he said. "They're quite vulnerable because of their life history."
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