The Cat Survives by a Hare
Despite an incredibly limited diet, the reclusive lynx continues to thrive in the most inhospitable places
Long ago, the predator lynx took a risky evolutionary turn: It hitched its fate to a single prey species, the snowshoe hare. Most mammals rely on a variety of foods, able to turn to other sources if one runs dry. But when hares are scarce, some lynx starve rather than switch.
If that weren't pressure enough, hare populations regularly plummet, which means lynx numbers also take frequent nose dives. The cat's troubles don't end there. Endowed with insatiable curiosity and a trusting nature, the lynx is easily trapped; human exploitation has already damaged some populations. A quarrelsome look-alike cousin — the bobcat — also prevents the lynx from expanding its range, keeping it sequestered in the Far North.
Some might say the lynx is jinxed. It came to North America across the frozen Bering Strait perhaps 200,000 years ago and thrived for centuries in boreal forests. Since European settlement, however, over-trapping and habitat loss have virtually eliminated the cat from southern Canada and most of the United States. The animal vanished entirely from this country's East Coast 100 years ago, and it is rapidly disappearing from its fragmented range in the Northwest.
In the past few years, severe population declines in some states along the Canadian border have set off a dispute between scientists and government officials over whether to shut down the lynx-trapping season. Some U.S. researchers argue that not only should trapping be halted, but the lynx should be placed on the list of threatened species.
Meanwhile, north of the Canadian border, the picture becomes somewhat rosier. After a few years of intense trapping pressure, the lynx have rebounded and, particularly in areas farthest to the north, are thriving. The cats' shy, secretive disposition makes it impossible to actually count their numbers, but scientists guess that tens of thousands of lynx roam the forested regions of Canada and Alaska. "Currently, there's no crisis with lynx, but we do need to be careful with them," cautions biologist Bob Stephenson of the Alaska Department of Fish and Game.
Though an average adult lynx weighs only about 22 pounds — barely twice the size of a house cat — it is a powerful predatory package of long legs, dagger-like fangs and inch-long claws. The cat sports a stubby 4-inch tail, a ruff of facial fur and a grayish-brown coat mottled with black. Its most prominent features are oversized feet, which make excellent snowshoes, and a tuft of hair jutting from each ear.
Keen vision and hearing help the cat locate the hares and, occasionally, the birds, rodents and caribou upon which it preys. "Long, driving legs in the rear and the perfect capture equipment in front make the lynx a very efficient predator," says Stephenson. "It's especially good at ambush and short pursuit." The cat often catches its prey with an explosive burst of speed. If that initial attack fails, however, the animal usually quits the chase to wait for another chance.
The lynx is one of three large North American cats. The cougar — with its much greater size, long tail and preference for large prey — is the more distant relative. The bobcat, which grows to about the same size as the lynx, is its virtual twin. Although the bobcat's feet are smaller, its ear tufts shorter and its tail distinctively barred, even experienced observers have trouble distinguishing between these cats at a glance. And a glance is about all anyone ever gets.
The bobcat also is more pugnacious, a fact that may explain the lynx's absence from huge tracts of suitable habitat. Biologists have long wondered why lynx don't live in more forests in the Lower 48 states; the hares are there, but the lynx are not. Not long ago, on Nova Scotia's Cape Breton Island, a Canadian researcher discovered what could be the answer.
In the 1950s, a new causeway allowed bobcats to emigrate for the first time from the mainland to Cape Breton, already teeming with lynx. Instead of mingling, though, the two cats divided Cape Breton — bobcats in the lowlands and lynx in the highlands. From 1977 to 1980, Canadian Wildlife Service biologist Gerry Parker studied the situation and concluded that the bobcat's cantankerous personality probably forced the mild-mannered lynx to retreat to the snowy high country.
Trappers have known for centuries that a captured lynx usually cowers and submits, while a bobcat often snarls, lunges and tries to attack. "The two cats probably don't thrash around and attempt to beat each other up," says Parker. "More likely, the bobcat simply pushes forward, and the lynx backs off." The lynx remains supreme in the Cape Breton highlands only because its huge feet provide mobility in deep snow where the bobcat cannot travel.
These characteristics — bobcat aggressiveness and the lynx's large feet — possibly explain why lynx live only in more northern climes and bobcats only in areas farther south. Generally, the boundary between their ranges follows the U.S.-Canadian border. South of that line, lynx prosper only where bobcats are scarce. "The evidence seems to indicate that the bobcat prevents the lynx from expanding its range," says Parker.
What most limits the lynx's mobility, though, is its near-absolute reliance on the snowshoe hare. When hares number in the thousands per square mile, a lynx with a home range of several square miles can easily make a living. During prosperous times, each cat kills a hare about every other day. With good nutrition available, virtually every female lynx breeds, litter size increases and cat numbers climb.
Hare abundance, however, is always followed by a population crash, caused in part by food shortage and disease. When hare numbers decline (sometimes to a few dozen per square mile), lynx suffer because they pursue other prey only reluctantly. "Lynx evolved to fill a specialized niche — that of a snow country, medium-sized predator of hare-sized prey," says Bob Stephenson. The cats are too small and too independent (they don't hunt in packs) to compete with wolves for most large prey, yet they're too big to subsist on tiny prey, such as mice.
Although few adult lynx actually starve when hares are scarce, kittens often do. Many females stop breeding, and those that do mate produce small litters, causing the cat's population to plummet. When hare numbers rebound, the lynx population also climbs until the next crash, which occurs about every ten years. Says Stephenson, "Lynx are tied to hares about as closely as a predator can be tied to its prey."
The gas and oil boom of the 1970s lured people to Alaska and northern Canada, and new roads were cut into previously remote lynx habitat. Soon, rising fur prices sent a virtual army of trappers into the woods. In 1972, a lynx pelt sold for about $70; by 1986, an average lynx skin fetched nearly $560. With prices so high, trapping pressure remained intense, even during times of cyclic lynx scarcity. "Trapping when lynx populations were low removed much of the breeding population," says Ted Bailey, a U.S. Fish and Wildlife Service biologist who studies lynx on Alaska's Kenai National Wildlife Refuge.
Again, the decline is impossible to quantify because of the cat's secretive nature. But "there's little doubt that excessive trapping caused a significant reduction in lynx numbers," says Arlen Todd, a biologist with the Alberta Fish and Wildlife Division. Then several things happened to change the lynx's luck. First, the bottom fell out of the fur market; since 1986, the value of a lynx pelt has dipped to about $100. Consequently, fewer trappers pursue lynx.
Perhaps more important in the long run are new management practices that seek to match trapping pressure with lynx availability. Throughout Alaska, officials periodically adjust trapping seasons to reflect local lynx numbers. The Kenai refuge has banned lynx-trapping temporarily and prohibits the use of traps intended for other animals that might accidentally catch cats. Some Canadian provinces restrict the number of lynx a trapper may take, and the Yukon registers trappers to make sure there's only one for each area.
Colorado, Wyoming and Utah do not allow trapping for lynx. Now, biologists concerned about shrinking populations in other northwestern states are trying to convince wildlife administrators to close their trapping seasons. So far, it is still legal to trap limited numbers of lynx in Montana, Idaho and Washington, although the allowable take has been reduced. "I find it difficult to justify a season at all," says Gary Koehler, a biologist with the University of Idaho's Wildlife Research Institute. No one knows how many lynx are left in Idaho. But if past harvest levels are any indication, the picture is grim: In the past decade, trappers have taken only about five lynx. "I'm a hunter and fisherman myself," says Koehler, "but I believe the species comes first."
For three years, Bruce Campbell — a biologist for the Montana Department of Fish, Wildlife and Parks — has urged the state to shut down its lynx-trapping season in his district. From 1976 until last year, he says, the annual lynx harvest in his region dropped from 127 cats to only 3. "I'm sure [trapping] is having a definite impact on the lynx population," he says. So far the state has responded only by lowering the harvest quota for the animals.
Lynx researchers, concerned with the animal's plight in the United States, nonetheless express hope for the future of the species as a whole. New management techniques in areas of the cat's greatest concentration should translate into continued healthy populations, they say. Meanwhile, comes more reason to cheer: Not long ago, scientists flew several dozen lynx from the Yukon to New York and released them into the species' former range in the Adirondack Mountains. "Predator restoration is an iffy thing, but I'm optimistic that these cats will make it," says project director Rainer Brocke, a wildlife ecologist at the State University of New York.
Eight of the reintroduced cats have died, mostly from collisions with vehicles, but researchers believe one pair has mated. That means the first New York-born lynx in a century may already be roaming the Adirondack woods. If these cats can create a self-sustaining population, other states with suitable habitat may also want to try lynx restorations. "With America's wild areas shrinking at an alarming rate," says Brocke, "it's imperative that we learn to accommodate lynx wherever the habitat permits."
Montana writer Gary Turbak wrote America's Great Cats (Northland Press, 1986), a book about lynx, cougars and bobcats.
