Dolphin may have 'remains' of legs

Bottlenose dolphinJapanese researches have discovered a bottlenose dolphin with an extra set of fins. They say that these fins could be the remains of hind legs. This discovery may provide further evidence that ocean-dwelling mammal once lived on land.

Fossil remains show dolphins and whales were four-footed land animals about 50 million years ago and share the same common ancestor as hippos and deer. Scientists believe they later transitioned to an aquatic lifestyle and their hind limbs disappeared.

Though odd-shaped protrusions have been found near the tails of dolphins and whales captured in the past, researchers say this was the first time one had been found with well-developed, symmetrical fins, Hayashi said.

"I believe the fins may be remains from the time when dolphins' ancient ancestors lived on land ... this is an unprecedented discovery," Seiji Osumi, an adviser at Tokyo's Institute of Cetacean Research, said at a news conference televised Sunday.

The second set of fins much smaller than the dolphin's front fins are about the size of human hands and protrude from near the tail on the dolphin's underside. The dolphin measures 8.92 feet and is about five years old, according to the museum.

A freak mutation may have caused the ancient trait to reassert itself, Osumi said.

Link & Image: Washington Post
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