Stuffed Animals Help Scientists Learn How Sea Lion Moms Recognize Their Babies

Tending to a nursing newborn is hard enough, but sea lion moms have an extra challenge. To consume enough calories for themselves and their pups, they have to repeatedly leave their babies behind and swim out to sea to hunt. Each time the mothers return, they have to find their pups again. Australian sea lion moms use a pup's smell and the sound of its calls to recognize it. They also use sight—which scientists learned by creating fake, stuffed sea lion pups, and leaving them for mothers to either accept or attack. "Pups tend to cluster together in groups while the mothers are away," says Kaja Wierucka, a graduate student at Macquarie University in Australia. She and her research group have seen as many as 20 pups huddled together in a few square meters. When a mother returns from the ocean, she has to pick her own baby out of ...