Behavioral changes are also evident in young gliders. They begin to adopt the 'curled ball' posture, observed in adults when they were c. 70 days old. This posture reduces surface area, particularly on the ventral surface and the patagium which for a large period of time have much shorter fur than that of the dorsal surface, thereby reducing insulation when exposed. Simply by adopting this posture, a young possum was able to maintain its Temp. 5degree higher than that of animals that remained outstretched.
*Holloway-Geiser*

(ages include time spent in pouch as well as out of pouch)

its supposed to say 5 degrees higher

This is very interesting... they always look so comfy in when they're balled up. I assumed they used their wings like a built-in blankie. Seems legit.