A rare clouded leopard's birth at the Nashville Zoo marks a milestone that could help rebuild the mysterious Asian cat's population, officials said Thursday.

The male cub is the first clouded leopard conceived through artificial insemination with frozen sperm, zoo officials said.

The birth is the result of a project between the Nashville Zoo and Smithsonian's National Zoo. The father, named Hannibal, lives at the National Zoo in Washington. The mother, named Tula, was born and raised at the Nashville Zoo.

Clouded leopards are among the rarest of the world's cat species and have proved notoriously difficult to breed in captivity.

"It's been successful in other species," Rick Schwartz, president of the Nashville Zoo, said of method of conception. "But for some reason, clouded leopards just don't play by the same rules that other species do. It's probably the most difficult cat to breed in captivity."

Zoo officials in Nashville and Washington hope the successful birth using the technique will increase the population of captive clouded leopards.

The cub, which was born Wednesday, has yet to be named. Nashville officials say the lead researchers at the National Zoo will name it.

The animal will be hand-raised by zookeepers in Nashville to ensure that it survives.