Photos: Critically endangered gorilla born at National Zoo

The National Zoo in Washington welcomed an adorable baby gorilla on Saturday morning, and visitors may be able to catch a glimpse of the baby, who has not yet been named, as soon as Tuesday, according to Smithsonian's National Zoo and Conservation Biology Institute. 

The infant is a western lowland gorilla, which is a critically endangered species. 

Mom Calaya, 20, has been nursing the baby, the zoo said. Animal care staff say the infant has been clinging closely to its mother.

"We are overjoyed to welcome a new infant to our western lowland gorilla troop," Becky Malinsky, curator of primates, said. "Calaya is an experienced mother, and I have every confidence she will take excellent care of this baby, as she did with her first offspring, Moke. Since his birth in 2018, it's been wonderful seeing her nurturing and playful side come out. I encourage people to visit our gorilla family and be inspired to help save this critically endangered species in the wild." 

Zoo staff are leaving the mom and baby alone to bond, so they have not yet been able to determine the baby's gender. The zoo also closed the Great Ape House until Tuesday to give the gorillas a quiet space to bond. While the exhibit is reopening, Calaya and the baby will have access to a private, off-exhibit area.

Calaya and 31-year-old Baraka bred in September of last year, according to the zoo. In October, zoo keepers used a common human pregnancy test to confirm that Calaya was pregnant. They were able to give her ultrasounds throughout the pregnancy to monitor fetal development.

Baby western lowland gorillas weigh around 4 pounds at birth, according to the zoo. They crawl and ride on their mothers' backs starting around three months.

The newborn, its parents and Moke also live with a 41-year-old female named Mandara and her 14-year-old daughter, Kibibi.

This is the first time in five years a western lowland gorilla has been born at the zoo. 

Keepers said they're excited to see how 5-year-old Moke will interact with his new sibling. 

Mom Calaya is described as being protective and cautious. Dad Baraka has a relaxed and playful personality. Zoo keepers said "he has been very tolerant of his 5-year-old son's antics."

Scientists estimate that in the past 20 to 25 years, the number of wild western lowland gorillas has decreased by 60% because of habitat loss, disease and poaching. The species is native to Africa and lives in the forests of Gabon, Central Africa Republic, Cameroon, Angola, Equatorial Guinea and Congo.

Western lowland gorillas are quiet, peaceful and nonaggressive, according to the zoo.  Adult males weigh an average of 300 pounds and up to 500 pounds. They stand up to 6 feet tall. Adult females weigh from 150 to 200 pounds and stand up to 4.5 feet tall. 

Gorillas live for 30 or 40 years in the wild. In human care, gorillas may live into their 50s, according to the zoo.