The last few years accounts of mountain lions attacking and killing people have been reported from several western states. Given time, this may not be strictly a western phenomenon.

A new book, "The Beast in the Garden: A Modern Parable of Man and Nature" by David Baron (2004, $24.95, Norton) describes how mountain lions in the West have changed their behavior in response to a variety of factors. The focus of the book is the Jan. 14, 1991 attack and killing in daylight of Scott Lancaster, 18, behind his high school near Boulder, Colo. It's a chilling, cautionary tale. It's also a terrific read, and I strongly recommend it.

Just a few weeks ago, Arnold McClure, editor of the Valley Log in Orbisonia, Pa., published a story of nearly a dozen recent reports of mountain lion sightings. The Pennsylvania Game Commission pooh-poohs such accounts unless solid physical evidence of lions can be produced. To date, there has been no proof.

It's the same story in West Virginia. People report lions regularly but the division of wildlife wants more than anecdotal accounts.

Privately, some state biologists have conceded to me that people may indeed see lions, but they are escaped or released "pets." The official line remains that wild, naturally reproducing populations of eastern mountain lions were exterminated decades ago. In hushed voices and off the record, however, these same biologists long for the wilderness these big cats have traditionally represented.

But just because officials do not acknowledge the presence of mountain lions doesn't mean they aren't present, and it doesn't mean the east can't support them. Pennsylvania, West Virginia, New York and other eastern states have large areas of wild, remote country and healthy deer populations. Add to the mix growing numbers of people who build homes in remote areas to "get back to nature," and the scenario sounds a lot like the situation in Baron's book.

In the 1800s and early 1900s mountain lions were hunted to near extinction in the west and wiped out in the east. But in the last 50 years, circumstances have changed. Scenic communities such as Boulder attracted people who loved the outdoors and wild animals. Towns acquired open space and established extensive systems of parks and natural areas. That made those communities even more attractive to the outdoor crowd, so the human population grew. For safety's sake, this led to bans on hunting in these areas, so the deer population grew rapidly. Meanwhile, because mountain lions were so rare, they escaped persecution by man.

By the 1980s Boulder was a green community with lots of deer, parkland and a growing population of lions at the higher elevations in the nearby mountains. Over time, lion sightings became more common. Dogs and cats began to disappear from backyards. And, most importantly, lions changed their behavior.

Mountain lions have always been described as shy, nocturnal, wilderness animals that would avoid contact with man at all costs. It turns out, that was the case when man hunted them. As prey, they are ghost-like. But under man's protection in populated areas, lions grew bolder. They hunted areas where deer and pets were easy prey. They became more active by day and they lost their fear of man and came to view humans as prey.

When the cat that killed Scott Lancaster was found two days after his death, it was guarding its "kill." It treated Lancaster as it would any prey.

It's far from time to panic about mountain lion attacks on people here in the East. But just as coyotes have moved eastward and recolonized states east of the Mississippi River, so, too, may mountain lions. They are not limited to mountains. They originally occupied the entire continent and require only an abundant food supply and cover.

It's not a stretch to imagine that in the next 20 years lions will recolonize portions of the East. I predict they will. Wildlife agencies should be prepared.