During cold , wet periods , it curls itself into a tight ball to conserve energy .
On warm days , a koala may rest with its back against a branch or lie on its stomach or back with its limbs dangling .
During cold , wet periods , koala curls itself into a tight ball to conserve energy .
On warm days , a koala may rest with its back against a branch or lie on its stomach or back with its limbs dangling .