Prehistoric beaver pond found in Arctic

Mammalian skeletal remains found in a prehistoric peat bog in Canada's Arctic show the animals roamed far from the "Old World."

Canadian and American paleontologists excavated the four-million-year-old pond on Ellesmere Island in Nunavut.

The pond is now about 3,200 kilometres north of the modern tree line at a latitude of nearly 79 degrees north.

Richard Tedford of the American Museum of Natural History in New York, and Richard Harington of the Canadian Museum of Nature in Ottawa made the discovery.

The pair found species usually associated with a warmer climate than is found in the present-day Arctic.

They say the winter temperatures were about 15 C warmer than today.

The rich selection of mammals include:

• an extinct bear
• wolverine
• Asian badger (Arctomeles),
• three-toed horse
• a musk-deer

Dipoides, a now extinct "Old World" species of beaver that is a distant relative of today's dam builders, was also found preserved in the pond.

"This deposit contains direct evidence of the composition of an Early Pliocene arctic mammalian fauna during an active period of interchange between Asia and North America," they wrote in Thursday's issue of the journal Nature.

About four to five million years ago, the mammals appear to have adapted to the colder climate as they migrated across what was once a land bridge over the Bering Sea, the researchers said.

They added the Beaver Pond site is dominated by Eurasiatic species.

The peat also contained well-preserved tree and plant remains including tree trunks and branches with beaver teeth marks, according to the study.