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. In addition they back-calculated the shark’s dimension by means of its earliest years, and located it may need been greater than six and a half ft lengthy when it was born.
“That’s a very massive child,” mentioned Mr. Cooper, who was not concerned within the examine.
To achieve such a staggering dimension, burgeoning megs could 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 reside younger. However the pups of some species don’t take kindly to roommates: As soon as hatched, they may start to casually devour their unhatched siblings, which helps them beef up earlier than being born.
“It’s this massive, calorie-dense, nutritious meal that may assist these embryos get larger, sooner,” mentioned Allison Bronson, who research the evolution of fish at Humboldt State College in Arcata, Calif., however wasn’t concerned within the examine.
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 an excellent 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 examine offered essential knowledge on a poorly understood animal. However he famous that some calculations it used have been based mostly on knowledge gathered within the Nineties, when researchers relied extra closely on nice white sharks to estimate elements of megalodon anatomy. Drawing too shut a comparability between the 2 animals, he mentioned, may end up “in underestimations in some particular physique dimensions.”
It’s additionally exhausting to understand how consultant this one particular person megalodon was of its species, Dr. Bronson mentioned. “There’s quite a lot of variation in fishes,” she mentioned. “Even fish of the identical age, identical species, can develop at actually totally different charges and attain actually totally different sizes.”
Researchers can’t understand how troublesome carrying and birthing a six-foot-plus pup may need been for megalo-moms. However “proportionally, whereas that child is de facto massive, so is the grownup,” 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.