Colorado’s Top Predator

Jeff Mitton

Natural Selections (Appeared in the Daily Camera December 18, 2004)

            After we exterminated wolves and excluded hunters from the Boulder Mountain Parks and Open Space, mule deer thrived and became abundant. Now puma are thinning the herds of deer.

            Puma concolor has many colloquial names: puma, mountain lion, cougar, panther, catamount. Pumas have the largest distribution of any land animal in the Americas. They are distributed from the southern tip of South America through Central America to Alaska. They once ranged from the Atlantic to the Pacific in North America, but they have disappeared from most places along the east coast and in the Midwest. However, the pumas referred to as Florida panthers are making a comeback in the southwestern portion of the Florida peninsula.

            Pumas are big cats; males can grow to 8 feet long and 250 pounds, and females can reach 7 feet and 140 pounds. Their tails account for 1/3 of their length. Pumas are slender with large feet and a relatively small head. They are agile and strong, and can leap 45 feet horizontally or 15 feet vertically.

Kittens have dark spots, but the spots disappear as the kittens mature. In adults, the belly, chest and throat are white, the ears and tip of the tail are black, and all else is a uniform color of gray of brown.

Although puma reproduce virtually year round, most kittens are born in summer or early fall. The gestation time is three months, and litter size varies from 1 to 3. Kittens weigh up to one pound at birth, and they stay with their mother until they are almost two years old. Pumas are elderly at 9 years, but a few have lived 13 years.

            In contrast to wolves, which are coursing predators that exhaust their prey, pumas are ambush predators. They crouch, motionless and concealed, until an animal comes close. Then they rush, catch the prey off guard, and drag it down, often dispatching it by breaking its neck. Mule deer and white-tailed deer are the most common prey; an adult puma kills about one deer per week. Pumas also take moose, elk, bighorn sheep, pronghorn antelope, rabbits, squirrels, raccoons, and squirrels. One puma, guarding a deer carcass, killed  a golden eagle that came to share the deer carcass.

            A home range is the area used for hunting and rearing offspring. Females have a home range of 20 to 70 square miles, while males use 35 to 150 square miles. Home ranges can overlap extensively, but pumas are solitary except for the time they are breeding.

            Accurate census data are not available, so we do not know how many puma live in Colorado or in the west. But the numbers of puma killed by hunters gives some indication of their abundance. Pumas are hunted with packs of dogs. A puma does not flee far, but soon takes refuge in a tree, where it is an easy target. In recent years, hunters killed about 370 in Colorado each year, and between 3,000 and 3,500 in ten western states (puma hunting is prohibited in California). I suspect that these harvests cannot be sustained; if quotas are not reduced, puma will disappear.

            Are puma a threat to humans? They will stalk solitary children, and may pursue fleeing adults. But they usually back down if an adult faces and confronts them. Since 1890, only 17 humans have been killed by pumas in the west, and only 2 or 3 have been killed in Colorado in the last 115 years. To put that toll in perspective, many more people are killed by lightning, or black plague, or bee stings, or hunting accidents.