Cetacean Scatology

For the want of dung, many whales have been lost. Cetacean feces can show what the animals eat—crucial information for protecting their habitat—but it disperses quickly in the ocean. The only reliable way to study whale diet has been to slaughter some of the animals and examine their stomachs. But Nick Gales, a biologist with the Australian government's Antarctic Division, has found a way to extract dietary data from what minute samples of whale scat remain floating on the waves. Using DNA fingerprinting, he can deduce exactly what prey a whale has consumed, which individual excreted the waste, and even whether the animal has intestinal parasites. Gales sees this as a powerful tool for protection: "In order to know the impact of commercial fishing on a species, you need to know exactly what the animals are eating, and whether they are turning to alternate food sources." He has already used his DNA test to track such dietary changes. The new emphasis on excrement also puts additional pressure on governments that support whaling. "It does away with what had been considered an accepted reason to kill already threatened animals," Gales says.