Males are larger than females. Cougars have long, slender bodies and small, broad, round heads. Ears are short, erect and rounded. The muzzle, chin and underparts are a creamy white. Black coloring appears on the tip of the tail, behind the ears, and at the base of the whiskers on the sides of the muzzle.
Immature cougars are paler, with obvious dark spots on their flanks.
Females mate every two to three years and produce a litter of two to three cubs. There is no set breeding season, however most births are in the spring. At six months of age, the cubs weigh 30- 40 pounds. They leave the den at this time, accompanying the female to her kills and occasionally hunting with her individually. A young male may leave at one year of age, but most cubs remain until they are nearly two.