Philadelphia ? Deep in a cave in Mifflin County, Pa., surrounded by icicles and tilted slabs of rock, DeeAnn Reeder shone her headlamp on a tiny bat.

It was dead.

Cradling it in gloved hands, she stretched out its wings, fanned out its minuscule toes, and examined its snout.

“I’ve seen worse,” Reeder whispered, “but, boy … he’s just covered in fungus.”

The Bucknell biology professor studied the bat. She knew it was white-nose syndrome, first discovered three years ago in a cave near Albany, N.Y. Bats that should have been hibernating inside were dead on the ground outside.

Since then, a million bats have died in the Northeast. Some caves have had 99 percent mortality.

In a growing mystery, white-nose spread last year to Pennsylvania and New Jersey.

The latest models predict the little brown bat, the most numerous in the nation, could be extinct in seven to 30 years.

“That’s incredibly fast,” said Greg Turner, the Pennsylvania Game Commission’s endangered-mammal specialist. “Unprecedented is the word.”

“Humans have done a pretty good job of killing a lot of animals, like the buffalo,” he said, “but nothing like this has ever been recorded. It’s pretty bleak. That’s the only way to say it.”

The bat decline echoes that of the world’s frogs. And colony collapse disorder among honeybees.

Some suggest links to pesticides or cascading effects of an altered environment.

White-nose isn’t just about bats. It’s also about bugs.

A lactating female can eat her body weight in insects in a single night. Scientists estimate the million bats lost so far would have eaten 694 tons of insects just last year.

Their diet includes crop pests and mosquitoes, which can spread West Nile disease and equine encephalitis.

“Bats have a real value in the environment. This is an ecological disaster,” said Jeremy Coleman, the U.S. Fish and Wildlife Service’s national white-nose syndrome coordinator. “If we lose them, I suspect that people will learn to appreciate them too late.”