Reproduction

Male bighorns are called rams, while females are known as ewes. Their offspring are called lambs, regardless of gender. During most of the year, males and females are separated into herds. However, in Fall all bets are off. Males leave their herds and search for miles for females that are in estrus. During this time males are at their best physical condition, ready to fight to prove his fitness amongst his species. If females are not yet ready for courtship, males will give chase to her. Sometimes as many as nine males give chase to a single female.

To determine if a female is in estrus, males expose their Jacobson's organ by curling their lower lip and expose it to the female's urine. If she is receptive, she may playfully joust a ram, usually the one of the biggest size. Having the biggest horns does not mean he is the most likely to produce offspring. Instead, a rams greatest reproductive fitness is about seven years of age, when his horns are almost at their greatest size and he is the most active. Then they mate, dozens of times in the course of a few hours. After the mating season, rams and ewes segregate again.

Then the winter months come. This is the most difficult time for bighorns, most difficult for food, most difficult for warmth, most difficult for survival. However, come spring new life is ready to be brought into the world. An ewe ready to give birth isolates herself from the herd and gives birth on a narrow ledge. After only a few days after being born, it is natural for lambs to wander off alone, to learn the rough environment. After about a week, the lamb is brought back to unite with the other ewes and lambs.