Smaller than brown and polar bears, the black bear was originally found throughout N. America but distribution is now fragmented (ref.). Around 16 subspecies are accepted by most authorities, this specimen is assigned to U.a.amblyceps. The teeth show the same variability in number of premolars as other bears, presumably indicating evolution towards omnivory.  This specimen has 3 upper and 3 lower premolars, four of which are vestigial.

1. American Black Bear skull, lateral view.
 
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Internet Resources

Standard references :
American Society of Mammalogists Monographs
Smithsonian / Wilson & Reeder's Taxonomic List
University of Michigan Animal Diversity Web

Skull Measurements (defined)

(all measurements in mm)

Specimen

CB

ZW

JL

IW

PC

NL

UT

NL

Comments

Illustrated

242

131

175

56

64

62

73

125

Smaller than average