Polar Bears, By Thomas Kokta, Issaquah, Washington, US

Polar Bears

Ursus maritimus

Learn more about Ursus maritimus from the Encyclopedia of Life

Encyclopedia of Life

Wapusk National Park,
Manitoba, Canada
By Thomas Kokta
Issaquah, Washington, USA

Two layers of fur help polar bears keep warm in the extreme temperatures of the Arctic. Adult females can weigh from 200 to 700 pounds and stand 6 to 8 feet tall. They give birth to their first cubs when they are between 4 and 8 years old. They have a very slow reproductive rate, normally producing only five litters in their lifetime. Pregnant females dig snow caves in the fall and give birth in early winter. A mother and her cubs spend their time sleeping until they emerge from their den in March or April. Cubs may stay with their mothers for as long as 2.5 years learning how to survive.

“This image was taken in Wapusk National Park on a frigid day. These polar bear cubs were very ‘clingy’ and didn't stray far from their mom, partly because of the -40° F temperature. The adult was very alert and protective, keeping close to the trees and constantly surveying the surroundings.” —TK

Canon EOS-1D Mark IV; EF 800mm ƒ/5.6L IS USM lens; 1.4x tele-extender; 1/1000 sec at ƒ/10; ISO 800; Gitzo tripod; Really Right Stuff head.