Sniffing butts isn't just for the dogs. Male lions can detect whether a female in his pride is in heat by smelling her reproductive organs. A lion pride consists of three to 30 individuals--many lionesses and a few males that have mating rights to the group. Females typically enter estrus at the same time, and over this four-day period they mate several times an hour. If the lioness fails to conceive, she will re-enter estrus about two weeks later and begin the mating cycle again.