Scans of a subset of its roughly lots of of vertebrae — some the scale of grapefruits — confirmed the shark had died on the age of 46. The researchers estimated the meg’s life expectancy to be round 88 to 100 years, implying that their specimen had been roughly “middle-aged,” Dr. Shimada mentioned. They additionally back-calculated the shark’s dimension by its earliest years, and located it may need been greater than six and a half ft lengthy when it was born.
“That’s a really big baby,” mentioned Mr. Cooper, who was not concerned within the research.
To attain such a staggering dimension, burgeoning megs might have snacked on one another whereas nonetheless within the womb, Dr. Shimada mentioned. Most sharks hatch from eggs inside their moms’ our bodies, then are birthed as stay younger. But the pups of some species don’t take kindly to roommates: Once hatched, they may start to casually devour their unhatched siblings, which helps them beef up earlier than being born.
“It’s this big, calorie-dense, nutritious meal that can help those embryos get bigger, faster,” mentioned Allison Bronson, who research the evolution of fish at Humboldt State University in Arcata, Calif., however wasn’t concerned within the research.
With that a lot heft in tow, mini-megs may need emerged able to duke it out with potential predators, or a minimum of dwarf a superb variety of them in dimension. A voracious urge for food, coupled with warm-bloodedness, may need helped them snarf down loads of prey, permitting the juvenile terrors to bulk up much more.
Mr. Cooper mentioned the research offered essential knowledge on a poorly understood animal. But he famous that some calculations it used had been primarily based on knowledge gathered within the 1990s, when researchers relied extra closely on nice white sharks to estimate points of megalodon anatomy. Drawing too shut a comparability between the 2 animals, he mentioned, may end up “in underestimations in some specific body dimensions.”
It’s additionally arduous to know the way consultant this one particular person megalodon was of its species, Dr. Bronson mentioned. “There’s a lot of variation in fishes,” she mentioned. “Even fish of the same age, same species, can grow at really different rates and reach really different sizes.”
Researchers can’t know the way troublesome carrying and birthing a six-foot-plus pup may need been for megalo-moms. But “proportionally, while that baby is really big, so is the adult,” Mr. Cooper mentioned. At most dimension, some megalodons may need spanned almost the size of a bowling lane — loads of area to deal with even a basketball-player-size embryo.