Extinct Short-faced Bear (Actodus spp.) Fact Sheet: Taxonomy & History

Like living animals, fossil remains of once-living animals are classified and grouped according to their relationships to each other and to their ancestors.

Common Name

• Short-faced bear
• Note: a new comprehensive study suggests this bear does not have a short face (Figueirido et al 2010)

Scientific Name

• Joseph Leidy named the genus Arctodus in 1854
• Arctos is the Greek word for bear; odus comes from the Greek word for tooth.
• Simus comes from the Greek word for snub or blunt-nosed

The bear family, Ursidae occupied North America for the last 37 million years; present bear diversity is much reduced compared to its fossil record.

The fossil record for bears is extensive. (Li et al 2007)

Plionarctosis the first tremarctine (the short-faced bears) (Tedford & Martin 2001, Li et al 2007)

• Found in 7 million year-old Late Miocene rocks of Oregon.
• Genetic evidence supports the divergence of this short-faced lineage from other bears at about 10 million years ago.

The first Arctodus fossils are found in Pleistocene rocks between 1.8 million and 300,000 years ago. (Hunt 1997)

Arctodus, the extinct short-faced bear, and Tremarctos, the living spectacled bear, are the last of the tremarctine lineage.

• In order to preserve the world's evolutionary diversity, spectacled bears deserve special conservation priority. (Agnarsson et al 2010)
• All other bears belong to the Ursinae subfamily with the single exception of the giant panda, classified in the Ailuropodinae subfamily. (McKenna and Bell 1997)

Arctodus became extinct around 11,400 years ago (uncalibrated Carbon 14 years) or about 13,000 calendar years (calibrated)

Describer (Date): E.D. Cope 1879 for Arctodus simus

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia

Order: Carnivora

Family: Ursidae (bears)

Subfamily: Tremarctinae (the "running bears")

Genus: Arctodus

Species: Arctodus simus - short-faced bear (extinct)
Species: Arctodus pristinis - lesser short-faced bear (extinct)

Agnarsson et al (2010)
Figueirido et al (2010)
Hunt (1997)
Kurtén (1968)
Kurtén & Anderson (1980)
McKenna and Bell (1997)
Tedford & Martin (2001)
Wayne et al (1989)
Li et al (2007)