A scan of a subset of approximately hundreds of vertebrae – some the size of grapefruits – shows that the shark died at the age of 46. The researchers estimated the lifespan of the meg to be about 88 to 100 years, indicating that their specimen was approximately “middle-aged,” Dr. Shimada said. They also calculated the size of the shark in its earliest years and found that it may have been more than six and a half feet long when it was born.
“This is a really big baby,” said Mr Cooper, who was not involved in the study.
To reach such a stunning size, thriving megas may have eaten while still in the womb, Dr. Shimada said. Most sharks hatch from eggs in their mothers̵
“This large, high-calorie, nutritious meal can help these embryos grow bigger and faster,” said Alison Bronson, who studied fish evolution at Humboldt State University in Arcata, California, but was not involved in the study.
With such a heavy pulling weight, mini-megaies may have appeared, ready to push it out with potential predators, or at least accumulate a large number of them. An insatiable appetite, combined with warm-bloodedness, may have helped them capture a lot of prey, allowing young horrors to accumulate even more.
Mr Cooper said the study provided crucial data on a misunderstood animal. But he noted that some of the calculations he uses are based on data collected in the 1990s, when researchers relied heavily on great white sharks to assess aspects of the anatomy of the megalodon. Making too close a comparison between the two animals, he said, could lead to “underestimation of some specific body sizes.”
It’s also difficult to see how representative this particular megalodon of its kind is, Dr. Bronson said. “There are a lot of variations in fish,” she said. “Even fish of the same age, of the same species, can grow at really different rates and reach really different sizes.”
Researchers do not know how difficult it would be to carry and give birth to a puppy more than a meter and a half long for megalo-mothers. But “proportionately, although this baby is really big, so is the adult,” Mr Cooper said. At maximum size, some megalodons may have covered almost the length of the bowling alley – enough space to accommodate even an embryo the size of a basketball player.