Koalas at risk from climate change

Eucalyptus leaves already have little nutritional value, he said, and koalas have adapted to their poor diet by sleeping to conserve energy.

"It's a very precarious existence," Tyndale-Biscoe said. "They basically sleep for 20 hours a day and then they've got four hours to do everything else -occasionally eat a leaf and maybe once a year go after another koala" to mate.

Tyndale-Biscoe said koalas had already disappeared from parts of Australia but remained plentiful in others and were unlikely to be wiped out by climate change. They already have been displaced from the most nutritious trees on the most fertile land by the spread of farms and suburbs, he said.