When I write these little essays, I usually focus on something triggered by what I’ve seen along the trails. This time, however, I’m writing about some large animals that I’ve never seen around here, although they live in our area and other folks in Southeast have seen them. Seldom seen, they are wide-ranging predators — cougar and lynx. There are over 30 species of wild cats in the world, and we have only those two.
We live near the northern edge of the cougar’s geographic range, which extends southward in western North America and throughout most of South America almost to Tierra del Fuego. Historically, cougars also ranged over much of the United States and southern Canada, but now they are only occasionally recorded east of the Rockies (except for a small enclave in Florida). Even within its current range, cougar populations have been reduced by habitat loss, diminished prey populations (partly due to hunting by humans), and direct persecution by humans.
Cougars (a.k.a. mountain lions or pumas) occupy many different habitats across their range; their inhabited areas are typified by good vegetation cover or rugged terrain — features that they use for stalking prey. Their principal prey in North America is deer, but they can take a beast of any size from moose to mouse; some individuals also prey on domestic livestock. Sometimes they eat birds or even insects if food is scarce. A typical pre-capture event includes a silent stalk, getting as close to the prey as feasible, followed by a high-speed dash to bring it down. If a prey animal is not totally consumed after the kill, a cougar often covers the remains with leaves and twigs, returning to finish the feast later.
Male cougars in our part of the world usually weigh a 120 to 175 pounds; females are considerably smaller, at about 65 to a 110 pounds. One set of estimates found that an adult male would need to eat the equivalent of 35 deer per year, while a female with kittens would need the equivalent of about 50 deer per year. Cougars and other cats are reported to require the kidneys, livers and lungs of their prey, in order to get enough vitamin A for their metabolic needs.
As kittens grow up and leave their mothers, they establish home ranges — areas where they spend most of their time. Home range size varies in part with the abundance of prey. Home ranges of females are smaller than those of males and often overlap with each other. Male home ranges are larger, overlapping those of several females but not overlapping with each other. Once a female establishes her home range, she is not likely to move, but males may shift their location to increase access to females. A cougar usually matures usually at an age of 2 or 3 years, but is not likely to breed if it doesn’t have an established home range.
The usual litter size is two or three kittens, but sometimes up to six. Gestation takes about three months, and young ones are weaned when about 3 months old, although they start eating meat before that. They stay with the mother for one or two years before setting off to set up their own home range. If a new male cougar moves into an area, he may kill existing kittens, which brings the bereft female back into estrus and breeding readiness. This unlovely habit is known from a variety of animals.
Canada lynx range through the boreal forest from Alaska to the east coast of Canada and down the Rockies to Utah. They are sometimes reported from New England and the upper Midwest and, if forest prey is scarce, they occasionally explore the northern prairies as well. Lynx have been considered to be endangered in the Lower 48.
Lynx are much smaller than cougars; males weigh up to about 40 pounds, and females up to about 24 pounds. Their principal prey is the snowshoe hare, whose populations periodically peak and crash on about a 10-year cycle. Lynx populations peak and crash similarly, with lag of about one year. When hares are abundant, lynx have bigger litters and virtually all females bear young, but when hare populations crash, few lynx females have kittens, and any litter that are produced are small, and kitten survival is poor. Of course, when hares are scarce, lynx turn to other prey, from the size of deer to mice, to eke out a living. In severe food shortages, they are known to travel long distances in search of food, which accounts for those invasions of the prairies.
A typical litter is composed of three or four kittens (up to six or even seven in good times). Gestation takes about two months, and young ones usually mature when two years old (sometimes sooner when hares are abundant). Juveniles stay with their mother through their first winter and then disperse to find their own home range. Once a young lynx settles in an area, it is likely to stay there, if the prey supply is adequate. In general, the small home ranges of females do not overlap with each other, nor do the larger ones of males, but the home ranges of males typically overlap those of several females.
Lynx hunt by lying in wait, sometimes stalking, followed by a quick dash and pounce at close range. If not all the captured prey is consumed, the remains may be buried in snow or leaves for later consumption.
I’ve yet to see a cougar, but I happily saw a lynx, just once, on the Atlin road. My eyes caught a long-legged furry beast standing in the middle of the road, but it took my surprised brain a few seconds to realize what I was seeing. A few more seconds, and it was gone, into the forest, leaving behind an indelible image in my memory.
• Mary F. Willson is a retired professor of ecology.
