A number of factors influence shark growth and could have contributed to Deep Blue's unusual size, said Neil Hammerschlag, research assistant professor at the University of Miami's Rosenstiel School and Abess Center. Genetics certainly play a part; some individuals are naturally predisposed to be larger, and great white females are typically bigger than males, Hammerschlag said.
Environment and food supply are also important; plenty of nutritious meals would fuel steady growth, as could warmer waters. Great whites inhabit most seas and oceans, and average body size can also vary depending on where the population is found.
But Deep Blue wasn't just longer than the average great white; she was also very wide around the middle. Padilla pointed to her unusual girth as a sign of pregnancy. And being "50 and pregnant" isn't a big deal for a shark. Once females reach sexual maturity in their mid-30s, the sharks can continue to reproduce for the rest of their lives.
The number of young a shark births can vary, but litters with as many as 10 pups have been documented, said Tobey Curtis of the National Marine Fisheries Service. And bigger sharks are more likely to produce big litters, making larger females important from a conservation standpoint. "The more big females like Deep Blue that we have in the population, the better off the white shark population will be," Curtis told Live Science.
Glimpses of exceptionally large great whites like Deep Blue can help to shed light on the many unknowns of these elusive creatures. "There's a lot we still don't know," said Gavin Naylor, a biology professor at the College of Charleston. Great whites are especially difficult to raise and study in captivity, and as with any big marine animal, observing their habits in the ocean depths is challenging and often dangerous, Naylor added.
Technologies like satellite tracking are revealing more about great whites and their lifestyles, and scientists may yet discover that 50-something giants like Deep Blue are not so rare after all. "Sharks that live in deep, cold water could be much older - well over 100," Naylor said.
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