The Cheetah Curse

A pair of cheetah cubs born at the National Zoo in Washington have been hailed as a miracle, or at least a victory, in the science of breeding cheetahs. Since they were declared an endangered species, zoos can no longer import cheetahs from the wild, and breeding them became very important, not only for the sake of the zoos, but to help researchers keep them from disappearing altogether. Why are cheetahs so hard to breed in captivity? SciWrite has a fascinating three-part post on the history of cheetahs, their social structure in the wild, and the attempts to breed them in captivity. Oh yeah, and the story of Ally's difficult birth that resulted in the two cubs, Justin and Carmelita. From part two:

While some researchers started watching cheetahs from afar, another group took an opposite approach and starting collecting blood, urine, and stool samples. Written into the cheetah’s genes, researchers stumbled upon the cat’s dark history. Around 10,000 years ago, cheetahs nearly went extinct. An estimated 10-20 individuals survived, the ancestors of all living cheetahs today. Consequently, current “cheetahs have almost zero percent of genetic variability,” says Steve Bircher. They are “all like brothers and sisters.”

Could the lack of genetic diversity having a lingering effect? Studies of male cheetah sperm showed startlingly low sperm counts; about one-tenth the normal counts of lions, tigers, and domestic cats, according to Bircher. This was initially thought to explain low captive birth rates until it was realized that wild Namibian males with similarly low sperm counts reproduce just fine.

“Lack of genetic variability is not what has hampered the cheetah ability to breed,” says Bircher. “Quite simply, it’s how we managed cheetahs.”

Just above the title of each post the link to the next post in the series. More