麻豆传媒

Want to find out what whales eat? There鈥檚 no need to cut them open, just wait until they relieve themselves.

One of the reasons given by the Japanese government for its 鈥渟cientific鈥� whaling programme is to learn more about the animals鈥� diet. Now Stacy DeRuiter at the Woods Hole Oceanographic Institution in Massachusetts and her team have developed a way of investigating diet by identifying mitochondrial DNA from the remains of the prey in a whale鈥檚 faeces.

The team has collected samples from several cetacean species and discovered, for example, that faeces from Blainville鈥檚 beaked whale contain DNA evidence of bony fish, including gulper eel. It had been thought to dine primarily on squid.

鈥淚t鈥檚 now certainly the case that we can get as good diet information from DNA analysis of faeces as we can from dead whales 鈥� probably better,鈥� says Simon Jarman of the Australian Antarctic Division in Kingston, Tasmania, who also analyses excreted DNA.

Few scientists believe Japan鈥檚 whaling programme has much to do with science. Jon Copley, a marine biologist at the University of Southampton in the UK, says that in 2006 there were 488 papers on whales on the ISI Web of Knowledge database. 鈥淥nly 0.8 per cent of these came from Japan鈥檚 whaling programme or involved techniques that required euthanisation.鈥�

DeRuiter reports her results this week at the Society for Marine Mammalogy鈥檚 conference in Cape Town, South Africa.

Endangered species 鈥� Learn more about the conservation battle in our comprehensive special report.