No one is quite sure why it's happening, but it's created the kind of excitement zoos lust for. In the past three months, two chimps have given birth and a third is pregnant. And Toto, who is 45, has never shown sexual interest in anyone but himself. Bingaman thinks the vasectomies may have failed. Vasectomies are known to have a 1 percent failure rate in humans.
Chimps are very resilient.
Charles Sedgwick, the zoo's director of animal health sciences, thinks she's wrong. Sedgwick thinks Toto or perhaps the youngsters are the fathers. He said there have been rare cases of young chimps impregnating a female. The chimps at the Los Angeles Zoo have sex every day, Sedgwick said. The zoo started trying to curb its chimp population about eight years ago because the enclosure was getting too crowded and chimps aren't an endangered species.