PRAGUE (AP) — Prague's zoo says its attempt to breed critically endangered white-belted ruffed lemurs is on the right track.

David Vala, the zoo's chief primate curator, said Friday that three lemurs born April 22 have been doing well.

Vala said: "We haven't won yet, but we already have the most difficult period behind us."

Vala said it was difficult to breed this lemur subspecies because they can become pregnant just one day a year and mothers tend to completely neglect their babies.

That was the case twice before with Fania, the mother of the three babies who have yet to be named.

The zoo says there are only 88 similar lemurs in captivity. Around 10,000 live in the wild in their native Madagascar, down by 80 percent in the last 21 years.