The researchers were startled to find bears having to swim up to 60 miles across open sea to find food. They are being forced into the long voyages because the ice floes from which they feed are melting, becoming smaller and drifting farther apart.

Although polar bears are strong swimmers, they are adapted for swimming close to the shore. Their sea journeys leave them them vulnerable to exhaustion, hypothermia or being swamped by waves. 

According to the new research, four bear carcases were found floating in one month in a single patch of sea off the north coast of Alaska, where average summer temperatures have increased by 2-3C degrees since 1950s.

http://www.timesonline.co.uk/tol/news/uk/article767459.ece

[Show as slideshow]

Serene Bear on an ice float. 1

Another bear resting by the ocean.2

An increasingly frequent open ocean crossing. 3

Iconic image of a resting Polar Bear. 4

Greenpeace has a way with words.

We must also keep our humour in difficult times :) 5

Haunting picture of a drowned Polar Bear before the era of arctic thawing. 6

Iconic image of a resting Polar Bear. 7

A very tired Polar Bear makes it to an ice flow. 8