American black bear, Ursus americanus "Dinner Guest" by Bruce McKay via Flickr, Creative Commons Attribution ShareAlike.	Brown bear, Ursus arctos Rubund Creative Commons Attribution ShareAlike.
Grizzly bear, Ursus arctos horribilis "Grizzly 2" by Bruce McKay Yellow Snow Photography via Flickr, Creative Commons Attribution ShareAlike.	Polar bear, Ursus maritimus Rubund Creative Commons Attribution ShareAlike.
Asian black bear, Ursus thibetanus "Asian (Himalayan) Black Bear" by Crazy Creatures via Flickr, Creative Commons Attribution-NoDerivs.

Taxonomy:

American black bear, Ursus americanus

Brown bear, Ursus arctos

Ursus arctos alascensis (Add)
Eurasian brown bear, Ursus arctos arctos (Add)
Kamchatka brown bear, Ursus arctos beringianus (Add)
California golden bear, Ursus arctos californicus (Add)
East Siberian brown bear, Ursus arctos collaris (Add)
Atlas bear, Ursus arctos crowtheri (Add)
Ursus arctos dalli (Add)
Grizzly bear, Ursus arctos horribilis

Himalayan brown bear, Ursus arctos isabellinus (Add)
Ussuri brown bear, Ursus arctos lasiotus (Add)
Marsican brown bear, Ursus arctos marsicanus (Add)
Kodiak bear, Ursus arctos middendorffi (Add)
Mexican grizzly bear, Ursus arctos nelsoni (Add)
Tibetan blue bear, Ursus arctos pruinosus (Add)
Ursus arctos sitkensis (Add)
Ursus arctos stikeenensis (Add)
Syrian brown bear, Ursus arctos syriacus (Add)

Polar bear, Ursus maritimus

Asian black bear, Ursus thibetanus