The world’s most massive animal, the blue whale, is like a 100-passenger jet gliding below the ocean’s surface. Whales are among the largest organisms ever to exist, and now scientists say they may know when and why these majestic mammals evolved to be so enormous. In a study published in May in the Proceedings of the Royal Society B, researchers modeled the sizes of baleen whales that lived between roughly 35 million years ago and the present. The team measured the skulls of 63 extinct whale species from the fossil collection at the Smithsonian Institution’s National Museum of Natural History (skull size is a known indicator of body size).
