You'd need a whole new song to describe these baby sharks, and it wouldn't be cute. Scientists studying long-extinct megalodons estimate they were born 6.5 feet long, reports the Guardian. And one reason they emerged so large was that they likely snacked on their unhatched siblings while still in the womb, per the New York Times. Adult megalodons were among the biggest creatures ever to live when they ruled the seas about 20 million years ago. At roughly 50 feet in length and 110,000 pounds, they would dwarf a modern great white. The new study in Historical Biology is seen as the first to take a comprehensive look at what the sharks were like at birth. It made use of one of the best preserved specimens of an adult megalodon, and researchers were able to chart its growth by looking at growth bands, similar to tree rings.
"Proportionally, while that baby is really big, so is the adult,” shark expert Jack Cooper of Britain's Swansea University, who wasn't involved in the study, tells the Times. Researchers calculated that the particular shark they studied grew steadily throughout life, more than 6 inches a year, and reached a length of about 30 feet before its death around age 46, per Gizmodo. However, they say that megalodons were capable of living to roughly twice that age. And they apparently got a head start in life by devouring unhatched siblings while still inside their mothers' bodies. “It’s this big, calorie-dense, nutritious meal that can help those embryos get bigger, faster,” another shark expert, Allison Bronson of Humboldt State University in California, tells the Times. (The West Coast is seeing a shark baby boom.)