Four Lion Cubs Born at National Zoo in DC [VIDEO]

Four lion cubs were born at the Smithsonian's National Zoo in Washington D.C., the zoo announced Tuesday.

Shera, the zoo's 9-year-old African lion, delivered the cubs on March 2 over a 7-hour period, the zoo said.

The cubs all appear to be healthy and zoo officials said they are cautiously optimistic that the cubs will do well.

"Shera successfully raised her previous litter of four in 2010, so we're cautiously optimistic that these cubs will thrive," said Kristen Clark, an animal keeper at the zoo's Great Cats exhibit. "Like any new mom, she needs some peace and quiet to bond with her cubs, so we're giving her the solitude she needs. From what we've observed on the cam, her behaviors are right on point, and there's no need for us to intervene."

All four of the cubs are nursing, moving and vocalizing well, the zoo said.

Late last month the zoo announced it was temporarily disabling its lion cub webcams, which were trained on Shera's older sister Nababiep and her two newborn cubs. The zoo said that when the webcams were back online, it would be to give viewers a look at a new litter of lion cubs.

Zoo website visitors can now use four webcams to view the new mother and her cubs.

Both Shera and Nababiep's cubs were sired by Luke, the zoo's 8-year-old lion. The National Zoo takes part in the Association of Zoos and Aquariums' African Lion Species Survival Plan, a program that matches individual animals across the country for breeding in order to maintain a healthy, genetically diverse and self-sustaining population.

The zoo said it is on its way to establishing its own pride of lions. Most cats are solitary creatures, and the pride structure of lions is unique among big cats. The zoo said it is trying to emulate pride conditions the lions would have in the wild.

"At this time, both mothers have a den space to bond with their cubs that is separated from each other and Luke," said animal keeper Rebecca Stites. "In the wild, a lion may take up to six weeks to introduce her cubs to the rest of the pride, so we are emulating that process. Once Shera's behavior indicates that she's comfortable with the cubs meeting their half-siblings, aunt and dad, we'll begin introductions. Our aim is to bring all nine lions together."

The zoo said that the cubs will remain out of public view until later this year.

Currently, nine lions - two adult females, one male and six cubs - live at the National Zoo.