The mountain lion, or cougar, is the largest cat in Idaho and in the northern U. S. It has a yellowish color, often with some rusty, reddish color on its back. Its tail, which appears to be very long is cylindrical with yellowish on top and lighter color underneath. The tail has a dark tip. There is dark color between the ears and around the muzzle. Adult females may weigh 80 to 130 pounds (37-60 kg) while adult males may weigh 90 to 170 pounds (45-78 kg). Their total body length ranges from 60 to 108 inches (150-270 cm), tail length is 21 to 36 inches (51-85 cm).
The mountain lion had the widest historic distribution of any native American mammal other than humans, from British Columbia south through Mexico and central America to Argentina, and from the Pacific to the Atlantic coasts. Currently in the U. S. its populations are scattered in wild, mountainous, rugged terrain areas and seems restricted to areas with relatively sparse human populations. It is most widely distributed in the western one-third of the U. S.
They seem to prefer mountainous country with cliffs and rimrock, and semi-wooded canyon habitat with slopes of mixed open and forest. Mountain lions range over vast areas and thus can move through a diversity of habitat types.
The cougar relies heavily on mule deer, which may comprise up to 75% of their diet throughout the year. They are somewhat opportunistic, eating large and small mammals such as bighorn sheep, coyote, mice, squirrels, and rabbits. They also prey on porcupines and can actually pass porcupine quills through their digestive system, apparently with no ill effects. They even will eat some insects and reptiles. They do occasionally prey on livestock, primarily sheep and cattle. One Idaho study reported that mule deer and elk were their primary food from September-May, and Columbian ground squirrels were primary food in summer. A study in southern Idaho showed that mule deer were their primary food throughout the year.
They are active day or night throughout year and in all kinds of weather. In the absence of human disturbance, peak activity occurs within 2 hours of sunset and sunrise; near human presence, activity peaks after sunset. They are primarily solitary with the exception of females with kittens. population density is usually not more than 3-4/100 km2 (about 1/20 km2 in Big Cypress and Everglades regions, Florida). In Idaho, mutual avoidance maintains density of breeding adults below level set by food supply. Their annual home range varies greatly in different areas. In Idaho, home ranges of males were from 54 to 230 km2 , while females had home ranges of 14 to 148 km2. However, home ranges of up to 1454 km2 have been reported. Home ranges of resident females overlapped, but those of resident males did not, but one male home range typically overlaps 2 or 3 female home ranges. Seasonal movements occurred within home range in response to prey movements; mountain lions moved farther in summer than in winter while hunting their prey, and some altitudinal movement was associated with ungulate movements and snows in winter. In many areas of the Rocky Mountain states, mountain lions are found in residential areas that have been built in prime mule deer winter range. This, of course, is because mountain lions are following their prey. Males are known to kill kittens, which has been documented in an Idaho study. A radiotelemetry study has been ongoing in isolated mountain ranges of south-central Idaho for over ten years.
Gestation lasts about 82-96 days. Most births occur April-September. Litter size varies from 1-6. Young are weaned after 2-3 mo, remain with mother for 1-2 yr, and reproduce at 2-3 yr (Idaho study reported female breeding age may depend on social status). Usually 2 years elapse between litters (18-24 mo in Idaho), but if litter does not survive, female may have litters in consecutive years. Once bred, the female raises the young with no help from the male. The male leaves the female shortly after breeding.
Important State References:
Hornocker, M.G. 1970. An analysis of mountain lion predation upon mule deer and elk in the Idaho Primitive Area. Wildl. Monog. 21:1-39.
Holmes, B. R. 2000. The mountain lion in southeastern Idaho: population characteristics and a test of optimal foraging theory. M.S. Thesis. Idaho State University. 96 pp.