More recently, researchers have learned that fertile female cheetahs that are unrelated or have not been raised together should not be kept together because the nondominant female will experience so much stress that she stops going into heat.

To get around these problems for cheetahs and other animals, zoos are putting emphasis on conservation centers that are less like zoos and more like ranches or a safari park. The animal conservation center here has enough space to indulge the animals’ idiosyncrasies and mimic the wild.

The five centers that breed cheetahs now account for a disproportionate number of the victories, including an unusual case here in 2010.

A 5-year-old female cheetah had remained barren through many breeding attempts over two years. She had only a few prime years left, so a new male was trucked in from Florida, 900 miles away.

It worked. Born as a lone cub, the cheetah named Nick was removed from his mother’s care because of yet another research discovery: the cheetah alone among big cats will not produce enough milk for its baby if there is only one suckling. Anticipating that possibility, Dr. Crosier had timed another cheetah pregnancy to coincide with that of Nick’s mother.

As the center awaited the other birth, Nick was nursed with a bottle covered with cheetah fur so he would not grow too accustomed to humans. When the next birth — another singleton — took place, staff members waited until the new mother wandered off to eat and then placed Nick alongside the new baby, rubbing him with its bedding so he would absorb the smell.

When the mother returned, staff members held their breath: she could easily kill him with one snap of her jaws. Instead she adopted him and nursed both cubs. It was the sixth such transplant in American zoo history.