Zookeepers in New Zealand are celebrating the rare birth of triplets among one of Asia's most at- risk animals as part of an international breeding program.

The three male Nepalese red pandas were born at Hamilton Zoo on Dec. 20 last year, doubling the zoo's red panda population, the zoo announced Monday.

The cubs were doing well and the mother was doing an exceptional job, but they would only go on public view when they are about three months old, curator Sam Kudeweh said in a statement.

"Red panda cubs are slow to develop so the first months are really crucial. We have been undertaking regular weigh-ins with the cubs so that we can keep an eye on their progress, but need to balance this with a hands-off approach as much as possible," Kudeweh said.

The cubs were first weighed at 19 days old, when they were around 225 grams, but had since grown to 400 grams.

"We are really pleased to be able to contribute to the survival of the species with this breeding opportunity," she said.

In February last year, Hamilton Zoo announced that it had successfully bred its first red panda -- the survivor of twins -- after receiving authorization from the breeding program.

The program restricts the numbers of red pandas -- believed to number fewer than 10,000 in the world and decreasing -- bred each year in order to properly manage their captive environments and to ensure variations in the gene pool by allowing breeding age animals to be exchanged among zoos.

Like the giant panda, the red panda almost exclusively eats bamboo shoots, but it is spread over a larger area around the Himalayas, with the western subspecies living mostly in northern India, Nepal and Bhutan and the Styan's red panda mainly in China and northern Myanmar.

Classified as "vulnerable" by the International Union for Conservation of Nature, the red panda is threatened in the wild by deforestation and habitat fragmentation, as well as poaching for their fur.

Their scientific name is Ailurus fulgens, meaning "fire-colored cat" although the species are not cats. They are a striking reddish-brown color with white facial markings and a striped tail.

Last month, Auckland Zoo announced the birth of a Nepalese red panda in December last year.