National Geographic : 2001 Jun
DRIVE TO SURVIVE Perpetuating the species is no easy work-lions copulate about 500 times for every litter produced. Once a female entices a male to mate, it's over quickly, and the female may discourage dawdling by growling and clawing at her mate. The process repeats after a brief interlude. Because of the Asi atic lions' small gene pool, 70 to 80 percent of sperm is deformed-a precarious ratio that can lead to infertility when lions are further inbred in zoos. Adhering to a strict breeding program, European zoos have boosted their Asi atic lion count to almost 60.