‘A shrinking polar ice-cap and shortening polar ice season has pitched the species to the fore-front of conservation concerns, so much so that the conservation groups including Polar Bears International now feel that the modern zoo community has an increasingly important role to play, which includes keeping and managing polar bears within collections long term.’

"We have presented the information necessary to rescind the Bernhardt Memo," first co-author Steven Amstrup, a zoologist with Polar Bears International and the University of Wyoming, told AFP, referring to the legal caveat which was named after an attorney in former president George W. Bush's administration.

Polar Bears in accredited zoos have a life expectancy of 23.4 years according to the Kansas City Zoo.

In the wild they live for an average of between 15 and 18 years, according to Polar Bears International.

Kansas City Zoo said it would make its annual contribution from the conservation fund to Polar Bears International in Berlin's memory.

Nora and Amelia Gray contribute to research into polar bear diets and how they may be affected by climate change, conducted by the zoo in partnership with Polar Bears International, the US Geological Survey and others.

'It's really cool to see that he's already playing,' Amy Cutting, vice president for conservation at Polar Bears International, a nonprofit organization said to the Anchorage Daily News. 'That's sending a great signal that he's thriving.'

Although the first choice is for polar bears to stay wild, 'we believe that modern zoos do provide a high quality of life for bears,' Cutting explained.