LibGuides: Polar Bear (Ursus maritimus) Fact Sheet: Physical Characteristics

Physical Characteristics

Attribute	Male	Female
Body Weight	Typically 350–600 kg (775–1,300 lb) Very large males up to 800 kg (1,760 lb)	150–290 kg (330–650 lb) Some can be larger.
Shoulder Height	Up to 1.7 m (5.6 ft)*	Up to 1.7 m (5.6 ft)*
Body Length	240–260 cm (95–102 in)	190–210 cm (75–83 in)
Tail Length	7–12 cm (about 3–5 in)	7–12 cm (about 3–5 in)

*Alaskan brown bear is nearly the same size.

Neck is long and very thick
- Wider than the head
Head elongated but smaller than that of other bears
Dentition reflects a strictly carnivorous diet
- Slicing teeth (carnassials) well-developed for eating flesh
- Canines elongated, conical and slightly hooked for grasping prey
  - Male canines very large
- Molar surface area reduced (infrequently chew plants)
Ears relatively small

Wide feet
- Large, paddle-like
5 toes on each foot
Claws non-retractable
- 5–7 cm long
Soles of feet have small dermal bumps or papillae
- May help with traction on ice

Large amounts of subcutaneous fat
- 5–10 cm thick in adults
- Both blubber and pelt provide insulation
Experience little bone loss during prolonged, continuous denning period (Amstrup 2003)
- Unique adaptation
Lack shoulder hump
Females have four functional mammae for nursing young
- Other bears have 6
Liver tissue is toxic to humans, if consumed, due to its high levels of vitamin A (Amstrup 2003)

Substantial sexual dimorphism (e.g., Derocher et al. 2005)
Males can be 2 times larger than females
Males have much longer foreleg guard hairs than females
- May be used by females to select mates, or may make a male look larger to other males

Few parts of a polar bear's body lack fur. Even their foot pads may be furred during winter.

Amstrup (2003)
Cushing et al (1988)
DeMaster & Stirling (1981)
Derocher et al (2005)
Kurt (1990)
Nachtigall et al (2007)
Stirling (1993, 1998)