A rare Sumatran tiger gave birth at the San Francisco Zoo over the weekend, providing the endangered species a critical boost.

According to a Reuters report, zookeepers were monitoring the pair in the zoo's secluded Lion House via webcam to allow the nine-year-old mother, named Leanne, and baby to bond with little human interference. There are estimated to be as few as 400 Sumatran tigers in the wild right now.

"All signs seem to be positive so far," Corinne MacDonald, San Francisco Zoo curator of carnivores and primates, said.

"Mom and cub are bonding," she said, adding the cub appeared to be healthy and was active and eating a lot.

Reports indicate that rare tiger cub was the the first of its kind born at the San Francisco Zoo since 2008, when Leanne delivered a litter of three males. The cubs were transferred to zoos across the United States. Before 2008, the zoo had not had a tiger birth in 30 years, Reuters reports.

Zoo staff will not know the gender of the newborn until its first examination in at least two weeks from now.

"These births are definitely rare," said Tara Harris, a tiger specialist with the North American-accrediting group Association of Zoos and Aquariums. About 75 Sumatran tigers are in captivity in North America and give birth to two to four litters a year, she added.

The cub was reportedly fathered by a six-year-old tiger named Larry, who was temporarily transferred from the Audubon Zoo in New Orleans for breeding. The unnamed cub will stay at the zoo for 1-1/2 years before zookeepers decide whether to transfer it.

Sumatran tigers -- the smallest of six tiger subspecies -- are found only on the Indonesian island of Sumatra in lowland and mountain forests. Habitat destruction and poaching are the main reasons for the tigers' endangerment, experts say.