CHICAGO (CBS) — A new baby gorilla was born at Lincoln Park Zoo Wednesday, according to a release from the zoo.

It’s the second new gorilla to join the western lowland gorilla troop. Bana, 24, gave birth to the healthy infant exactly one month after a male infant was born to Rollie on May 12.

The baby is staying tucked in close, clinging to Bana and has begun nursing, a spokeswoman for the zoo said. It is the second baby for Bana, who gave birth to female Patty in 2012.

Kwan, 30, the silverback of the family group, continues to watch Bana and the infant closely, the spokeswoman said.

The sex of the newborn is not known.

It joins a troop of eight, which includes two adult females, three juvenile females, Patty and the other new infant, which has also not yet been named.

Kwan and Bana were recommended to breed as part of the Western Lowland Gorilla Species Survival Plan, a collaborative effort among zoos accredited by the Association of Zoos and Aquariums, the release stated.

Western lowland gorillas are critically endangered in their native Central Africa due to poaching and habitat loss.

The Regenstein Center for African Apes will remain closed until Sunday, June 16, while the group acclimates to the two new arrivals. The building will then open intermittently.

There will be an member-only sneak peek June 15 and 16 from 10 a.m. to noon for Lincoln Park Zoo members.