As seen on a wire service Friday, January 14, 1994; SOURCE: Associated Press. DATELINE: WA
As seen on a wire service Friday, January 14, 1994;
SOURCE: Associated Press.
`COMPLETE' WHALE FOSSIL FOUND WITH HIND LEGS
Researchers have found the fossil remains of an ancient relative
of the whale that was able to walk on land.
"This critter is a missing link between land animals and modern
whales," said J.G.M. Thewissen, a paleobiologist at Northeastern
Ohio Universities College of Medicine in Rootstown, Ohio. "It is a
very complete specimen and has enough of the anatomy to teach us
something about how the animal moved on land."
A report on the discovery is to be published Friday in the
Thewissen said the fossil was found in deposits left by an
ancient sea that once existed in Pakistan. Fossils found nearby,
he said, suggest that the whale died about 50 million years ago.
"It was about the size of a big male sea lion and probably
weighed 600 to 700 pounds," said Thewissen.
Many fossils of the land-dwelling ancestors of the modern whale
have been found, but Thewissen said this is the first with enough
fossils of the legs, vertebrae and tail to show how the animal was
able to move on land and in the water.
The animal, which Thewissen calls Ambulocetus natans, had large
rear feet with fully developed legs. In front, the feet are short,
stubby and joined almost to the shoulder.
As a result, the walking whale actually moved by bumping along on
its chest and abdomen, just lifting itself enough to lurch
"That makes it look kind of clumsy," said Thewissen.
He said sea lions and seals appear clumsy on land, but they are
able to move short distances at a speed faster than most people
In the water, Thewissen said the ancient whale probably swam with
thrusts from its hind feet and legs. He said the bones suggest
there were large muscles in the back that would give the legs
great power for water propulsion.
Its tail, however, was probably long and lacked the distinct
fluke of modern whales, which swim by thrusting the tail fluke up
Ambulocetus natans had the teeth of a meat eater, but because it
was so awkward on land it probably was unable to catch prey out of
the water. For this reason, Thewissen speculates that the whale
ancestor lived on marine life, as do modern whales.
Modern whales are thought to have developed from animals that
lived on land and slowly, over thousands of generations, evolved
to the seabound mammal known today.
"The oldest skeleton that is a marine whale is about 40 million
years old," said Thewissen. That skeleton is 40 to 50 feet long
and had tiny hind feet. "Given the size of that animal, it is
clear that it couldn't move on the land."
Ambulocetus natans lived about 10 million years before that, but
Thewissen said there are a number of missing links in the
evolutionary chain that became the modern whale.
"The first true whale was probably about the size of a big wolf,"
said the researcher.
That contrasts with the modern blue whale which can be up to 100
feet long and weigh 220 tons.
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