For decades, scientists thought that flying squirrels could do little more than glide, controlling their descent from a high point to a low point. But most detailed observations took place in laboratory settings.

The laboratory is not where Alexander Badyaev prefers to be. Badyaev is a University of Arizona professor of evolutionary biology. He was born in Russia, so, when pronouncing the word "squirrel," he endearingly calls to mind Boris Badenov.

He regularly conducts flying squirrel research in the forests of Montana. A few years ago, he spent night after night staking out a corner of the Bob Marshall Wilderness. It was there that Badyaev saw a female leap up from a tree branch, unfurl her patagia — the winglike material that stretches from front legs to back legs — and soar away in level flight.