Whale CSI: why sperm whales are washing up dead on British shores

Scientists from the UK's Cetacean Strandings Investigation team are trying to determine the cause of the biggest mass stranding in a century

Slicing cleanly through two inches of skin and blubber, Rob Deaville considers the possible causes of death of the sea mammal on his dissecting table. "It's a female, juvenile, stranded in north Devon," he says. "No signs of parasite infestation. It looks healthy. It may have just come too close to shore."

This porpoise, in the process of being dismembered with small parts of its vital organs tested for disease and pollutants, is one of hundreds that come to the labs in the Zoological Society of London each year, awaiting a post-mortem - a necropsy, in the scientific term - that will help to establish how the animal lived and why it died.