The largest sharks ever to hunt in Earth’s oceans may have gotten so big thanks to their predatory behavior in the womb, scientists report October 5 in Historical Biology.
The idea emerged from a study that first analyzed the sizes and shapes of modern and ancient shark teeth, using those data to estimate body sizes of the fish. Paleobiologist Kenshu Shimada of DePaul University in Chicago and colleagues focused on an order of sharks called lamniformes, of which only about 15 species still exist today, including fierce, fast great white and mako sharks as well as filter-feeding basking sharks (SN: 8/2/18).
Well over 200 lamniform species existed in the past, some of them quite large, Shimada says. But none is thought to have rivaled Otodus megalodon, commonly called megalodon, which lived between about 23 million and 2.5 million years ago. Determining just how giant these creatures were