The daily survival of the lynx - one of North America's rarest wildcats - has everything to do with timing.
After crouching alone, sometimes for hours, in a high-country forest, the slinky cat will finally explode across the snow, its saucer-sized paws acting like snowshoes as it leaps after its preferred prey, the equally nimble snowshoe hare.
For humans too, saving the lynx is a matter of deciding when to act.
A $1.5 million plan to restore this threatened species by importing 200 cats into the Colorado Rockies from Canada is sparking a debate over how quickly the state should move to save these alpine felines.
Colorado officials argue for pouncing quickly to thwart extinction. But a coalition of environmentalists is pushing for a go-slow pace so that thorough research can be done on whether imported lynxes could actually survive in their new home.
The debate resonates widely, coming during an era of numerous high-profile reintroduction efforts - from the black-footed ferret to the gray wolf to the tiny and warty boreal toad.
Furthermore, the fact that this debate is over how - not whether - to save the lynx may well signal a shift in how the nation thinks about saving endangered species. In contrast to the spotted-owl vs. loggers debate of several years ago, many of the current reintroduction efforts seem to have the backing of a majority of Americans.
In Colorado, those opposed to the fast-moving lynx plan point out that no one knows what caused the cats to disappear. Reintroducing them before addressing the root causes could harm the newcomers, they argue.
They note the last attempt to reintroduce lynx in the United States - in New York's Adirondack Mountains several years ago - ended badly. Unaccustomed to the hazards of roadways, most of the wildcats were struck by cars and killed.
"We want to see lynx brought back to Colorado, but we don't want it done in a way that guarantees their quick demise," says Rocky Smith, an ecologist with the Colorado Environmental Coalition in Denver. "Why bring back lynx, only to make them disappear again?" he says. "This is putting the cart before the horse."
But wildlife officials emphasize that past efforts, including failed restoration attempts, help refine biologists' understanding. "Science is based on the knowledge of others, and we learn from the successes and failures of others," says Todd Malmsbury, spokesman for the state wildlife division.
He also says that the state, which is being assisted by the US Fish and Wildlife Service (FWS) in the lynx effort, will continue to study the habitat and the numbers of snowshoe hare before signing off on the plan. "We're not going to drop 200 animals out there in the wild unless we know there's a good chance they're going to survive," he says.
For many activists, that assurance isn't enough. "Our concern is that if they are going to do this, they need to do it right," says Ted Zukoski, attorney for the Land and Water Fund in Boulder. "We're worried that in their rush to get this done, we'll get a program that fails. And we won't even know why."
Indeed, some environmentalists, including Mr. Zukoski, would rather wait for the lynx to be put on the federal government's endangered-species list, thus triggering a massive protection effort nationwide. These advocates worry that Colorado's lynx program could forestall the felines' inclusion on the federal list by boosting their numbers in the Rockies. Federal officials counter that the efforts in just one state won't affect their decision on listing the species for the entire nation. In fact, the cat is currently wait-listed for getting endangered-species status.
A stealthy loner
Lynx, which weigh about 25 pounds, look just like bobcats, except for the long, black tufts on their ears. They have short, black-tipped tails and broad, well-furred paws. Lynx often live and hunt alone, although they do mate for life. These shy felines are known to scamper away from humans, making them especially hard to spot.
They have long ranged throughout much of the Northern US. But in the past decade, they've been seen only in Montana, Wyoming, Alaska, Washington, and Maine. The last confirmed lynx sighting in Colorado was in 1974 - although state biologists have documented a few lynx tracks in recent years.
While bobcats and mountain lions continue to thrive in the Colorado Rockies, lynx numbers have dropped mysteriously. Scientists believe reintroduction is one of the best ways to study lynx, and thereby provide answers.
Under the current plan, lynx relocated to Colorado would be radio-collared and watched closely, to help ensure their survival.
Still, opponents of the plan question the value of such monitoring for improving understanding of indigenous lynx. "This being an alien population they're bringing in, what can they expect to learn from them?" asks Mr. Smith, whose organization represents some 50 wildlife groups - including the Sierra Club and the Audubon Society.
Federal wildlife experts do agree with environmentalists on one point, however: There's no guarantee that introducing a fresh crop of a threatened species will lead to a successful recovery.
"You have to be careful with reintroduction. You can't use it as a wholesale solution to recovering a species," says Lee Carlson, an endangered-species specialist with the FWS. "You need to ask why you lost them in the first place."
Yet in most cases, he says, benefits of reintroduction outweigh risks.
"Anytime you lose a species, you create a hole in the environment that's analogous to removing a brick from a wall," says Mr. Carlson. "And if you keep taking out chunks, eventually the whole wall falls down."