''Protarctos'' is an extinct genus of ursine bear that lived in North America during the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Asiatic black bear The Asian black bear (''Ursus thibetanus''), also known as the Asiatic black bear, moon bear and white-chested bear, is a medium-sized bear species In biology, a species is the basic unit of classification and a taxonomic rank of an or ...

. Originally described from a tooth found in

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyomi ...

, more complete remains of this species have been found in Ellesmere Island, Nunavut,

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

Palaeoecology

''Protarctos'' would have lived in a northern boreal-type forest habitat, where there would have been 24-hour darkness in winter, as well as about six months of ice and snow. Fossils of two different specimens, one a subadult, show signs of dental cavities which suggests its diet included high amounts of fermentable carbohydrates. This is the first and earliest documented occurrence of high-calorie diet in early bears, likely related to fat storage in preparation for the harsh Arctic winters.

References

Prehistoric bears Pliocene mammals of North America Prehistoric mammal genera {{paleo-carnivora-stub