Most of the mammals that live in Colorado National Monument on a year-round basis have evolved unique physical and behavioral adaptations to survive in this semiarid ecosystem. Annual precipitation at Colorado National Monument is less than 12 inches a year with summer temperatures ranging from the high 90s to over 110 degrees in the canyons. Winters are generally mild with lows occasionally dropping to the single digits. These extremes, combined with a minimal amount of water, can prove to be challenging to wildlife.
A majority of mammals like the desert cottontail, mule deer, coyote, porcupine, black-tailed jackrabbit, and many songbird species are crepuscular, meaning they are only active in the early morning hours or late in the evening when temperatures are cooler and there is just enough light to forage for food. Others, like the ringtail, fox, bobcat, mountian lion, several species of bats, and a variety of small desert rodents, are nocturnal (emerging at night) and are rarely seen.
Mammals like rock squirrels, antelope squirrels, and Hopi chipmunks are active during the daytime or "diurnal" and are a common sight. Of course, there is the occasional rare and exciting report of a mountain lion wandering in one of the canyons or, as was the case in the summer of 1997, a black bear sleeping in Window Rock!
Over 40 species of mammals have been recorded within the boundaries of the monument; however, not all are year-round residents. The desert bighorn sheep are frequently seen near the Balanced Rock area on the west side of the park. Elk have also been known to travel down to the monument from the higher elevations during the winter months.
Common Mammals in the Monument
Coyote (Canis latrans) – These medium-sized members of the canid family are commonplace in the American West. Coyotes average about 15 inches in height (at the shoulder) and weigh about 40 pounds. They are primarily nocturnal, but they can sometimes be spotted roaming in daytime. As an omnivore, they will eat almost anything, but small rodents and rabbits typically comprise the bulk of their diets. Coyotes breed in the winter and typically give birth to 5 to 10 pups in early spring. This inquisitive and opportunistic animal is the best runner of the canids, reaching speeds up to 30 miles per hour. They are able to leap up to 14 feet in a single bound.
Grey Fox (Urocyon cinereoargenteus) – The grey fox ranges through most of the southern half of North America. These small members of the canid family resemble small dogs with bushy tails. Grey foxes are solitary hunters and eat a wide variety of food, including rabbits, voles, mice, and birds; they also supplement their diets with fruits when they are available. Grey foxes are unique among canids in that they are able to climb trees. They have strong, hooked claws that allow them to scramble up trees to avoid predators or to get fruit. Grey foxes are nocturnal and den during the day in hollow trees, stumps, or old burrows.
Ringtail (Bassariscus astutus) – This cat-sized carnivore resembles a small fox with a long raccoon-like tail. Its tail is typically as long as its body and is banded with 14 to 16 alternating black and white rings. Ringtails live in a variety of habitats, but have a preference for rocky areas, canyon walls, and talus slopes. They are expert climbers, capable of climbing vertical walls. Ringtails are nocturnal and spend most of the day asleep in dens, typically in rock crevices and hollows. They eat a wide variety of animals, including small mammals, birds, reptiles, amphibians, and insects, but they also supplement their diets with fruit, including juniper berries, in winter.
Rabbits and Hares (family Leporidae) – Worldwide, there are almost 50 species of rabbits and hares, most of which are native to North America. At Colorado National Monument, desert cottontails (rabbits) and black-tailed jackrabbits (they are actually hares) are common. They are generally grazers, feeding on grasses and other plants, but they may also feed on twigs and tree bark. While these two groups of mammals are often confused, they are actually quite easy to identify. Rabbits are generally smaller and have relatively smaller ears. Hares have very large ears and long hind legs. Typically, rabbits are weak runners, and when threatened, they often scamper into thick brush. Hares, on the other hand, are more adapted to open country, are very strong runners, and usually burst into bounding runs when threatened. Both groups have high reproductive rates; their litters typically consist of up to eight young, and can be as large as 15.
Porcupine (Erethizon dorsatum) – These large members of the rodent family have long, pointed spines, or quills, growing from their backs and sides. The quills have needle-sharp ends and hundreds of barbs. They are loosely attached and can be raised by the muscles of the skin. Porcupines can be found in wooded areas throughout North America, from Alaska to Mexico. They are herbivorous that often eat the bark of trees. They grow to a length of about 26 inches, and have short tails and brownish hair that almost conceals their two to six inch quills.
Bobcat (Lynx rufus) – These medium-sized cats live in shrubby country and broken forests and are fairly common in the monument. Bobcats are about 25-30 inches in height (at the shoulder), and can weigh up to 60 pounds. They are gray-brown with distinctive black spots, and have short "bobbed" tails that are about four inches long. Bobcats are skilled predators. Their prey include rodents, rabbits, hares, squirrels, and birds. They are excellent climbers and often wait in trees to pounce on their prey. Bobcats are territorial; they mark their territories with urine, scent from anal glands, and feces deposited on the ground during their frequent territory patrols. Bobcats often wander large distances, sometimes 25-50 miles, but normally stay within a few miles of their territories. The territories of males are larger than those of females. While bobcats are solitary in nature, the two sexes do remain together briefly during the breeding season, and it is not unusual for the male to help provide food for the kittens. They usually mate in late winter and kittens are born in early spring. The kittens weigh less than one pound at birth and are blind and completely helpless. They normally venture from their dens at the age of five weeks, and by nine months are nearly independent.
Mountain Lion (Felis concolor) – Mountain lions, also commonly known as cougars and pumas, range from northern Canada to the tip of South America. They are large, powerful cats, standing 28 inches (at the shoulder) and weighing up to 200 pounds. Despite their large size, they are very quick and agile; mountain lions can cover up to 23 feet in a single leap. However, because they tire quickly, they must be accurate; if prey is able to survive initial attack, it will normally escape. They generally hunt in the daytime by stalking and pouncing on the back of their fleeing prey. Once they power their prey to the ground, they normally deliver a fatal bite to the back of the neck. Their principle food source is deer. Mountain lions have very large territories that rarely overlap. On the unlikely chance that two of these solitary cats meet, they rarely fight to defend their own territories. During the breeding season, male and female mountain lions hunt together and sleep next to each other. The female gives birth to cubs in a well hidden den, usually between rocks or in a cave. The cubs are spotted at birth, and they lose these spots at about six months of age. Although they can hunt for themselves at nine months of age, they normally stay with their mothers for two years. There are many tales of the savagery of mountain lions and their attacks on people, but unprovoked attacks are very rare. They usually avoid contact with humans, but if cornered, they can be very dangerous and should be treated with respect and caution.
Did You Know?
With a large head and powerful jaws, the collared lizard is a carnivore. If you wonder why this lizard will hang around long enough for you to take its picture, know that the lizard is protecting its territory! More...