A tiny Spanish fossil just doubled how long weasels have been around

A recent study has unveiled a groundbreaking discovery that effectively doubles the known evolutionary history of the weasel family.

3 min readUW News
A tiny Spanish fossil just doubled how long weasels have been around
Researchers, including Chris Law, a UW principal research scientist in the biology department, have determined that a fossil that was discovered in Spain belongs to a new species dating back to around 6.5 million years ago. This new species was likely similar in size to the smallest living weasel species today, the least weasel, shown here. Photo: iStock
From UW News

Weasels are small carnivores with a long body and short legs. They also have a stout skull and sharp teeth. These creatures, along with ferrets and minks, make up the Mustelinae subfamily.

Until now, researchers believed that the oldest fossils from this family were from Poland and Germany, dating back to about 3.5 million years ago in the Pliocene epoch. But a fossil discovered in Teruel, Spain, has doubled that estimate, dating back to the late Miocene, around 6.5 million years ago.

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Briefing

Source
UW News
Published
April 15, 2026