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London Whale Died of Dehydration, Autopsy Shows

James Owen in London
for National Geographic News
January 25, 2006
 
The whale that spent two days in central London after swimming up the
River Thames last week died from a combination of factors, including
dehydration and damage to her muscles and kidneys, experts say.

They add that the whale lost its way while hunting squid.

Results of an autopsy on the bottlenose whale, which didn't survive a last-ditch rescue operation, were released today.

Veterinary scientists who carried out the tests say the 19-foot-long (5.8-meter-long), four-ton mammal probably swam into the North Sea by mistake before heading up the Thames in an attempt to get back to the Atlantic Ocean (see map of the region).

The postmortem also suggests that British Royal Navy sonar was not a factor in the animal's death, as has been speculated, nor were injuries she sustained while she was in the river.

The sexually immature female died on a rescue barge as she was being ferried back to sea last weekend. The sighting drew huge crowds in London and worldwide media coverage.

Scientists examined the whale's carcass at a dockside near Gravesend in Kent and samples were then taken back to the Zoological Society of London (ZSL).

Veterinary pathologist Paul Jepson, of the ZSL, said the whale's death "is believed to be the result of a combination of factors, including severe dehydration, some muscle damage and reduction of kidney function."

Water Source

Jepson says whales and dolphins obtain water from their food and that northern bottlenose whales normally feed on deepwater squid in the Atlantic Ocean.

"This animal would not have been able to feed while in the North Sea and so it would have become dehydrated," he added.

Researchers say severe dehydration may also help account for damage to the whale's kidneys.

Further tests should show whether the whale had any bacterial or viral infection. Scientists are also analyzing samples for traces of pollutants such as heavy metals.

The whale's carcass has now been taken to London's Natural History Museum, where it will be added to the museum's research collection.

Richard Sabin, a zoologist at the museum, says the autopsy suggests the whale had been in the North Sea for several days before swimming up the Thames.

"The North Sea is quite a hostile environment for deep-diving whales like the northern bottlenose," he said. "It's a fairly shallow water body, and there's nothing for them to feed on."

Navigation Risk

"The coastline has very gently sloping, sandy beaches. And, as these animals are heavily dependent on echolocation to navigate, it can be difficult for them to detect when they are getting into shallower and shallower water [in this area]," Sabin added.

Animal-welfare groups had said that navy sonar or explosions at a coastal military site operated by a defense contractor may have disoriented the whale.

"It's not something that the postmortem has highlighted," Sabin said. "Paul Jepson thinks it's highly unlikely, and he's the most experienced person in the country regarding the effects of naval sonar on cetaceans." The cetacean order of marine mammals includes whales, dolphins, and porpoises.

Sabin adds that cuts sustained by the whale while swimming in the Thames were only superficial.

A team from the Natural History Museum collected the whale carcass yesterday. Soft tissue has now been removed from the skeleton, which will be stored and studied by researchers.

"The whale captured the imagination of the British public and of people all over the world, and now her legacy will live on," Sabin said.

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