In many respects, he is just like a human baby -- he's teething, learning to crawl and being fed out of a bottle every few hours. The time demanded in caring for this 12-week-old infant is also similar, requiring attention 24 hours a day.
But this infant will soon outgrow the arms of his human "parents." The 12-pound baby gorilla will weigh 400 pounds when he's fully grown, which will most likely be when he's in his late teens or early 20s.
"We're training him to be a gorilla, not a human," said Karen Vacco, assistant mammal curator for the Pittsburgh Zoo & PPG Aquarium. "We won't always be able to carry him."
The unnamed baby gorilla, at this point fondly referred to as "the little guy" by his caretakers, has been temporarily separated from his parents at the zoo because he wasn't developing properly. The baby was not vocal or moving in a manner expected of his age.
An examination determined his mother had a mammary infection that shut off her milk supply.
The baby gorilla has received special care from a handful of humans, the first time the Pittsburgh zoo has played the role of a parent for a baby gorilla, Ms. Vacco said. Now, the baby is doing well, able to walk a short distance on all fours and nibble on celery.
Fifteen-year-old Moka gave birth to the baby in Pittsburgh April 19. She also delivered a baby in February 2012, but he died just short of 4 months old.
Mrithi, the baby's 21-year-old father and a western lowland gorilla, was the first gorilla born at the zoo in Pittsburgh. The baby's birth is even more significant because western lowland gorillas are considered an endangered species due to loss of habitat, poaching and disease.
Moka, born at a Miami zoo, looked after her newborn son for four weeks, but gorilla keepers soon noticed that "something was a little off," Ms. Vacco said.
Mother gorillas usually are not willing to be separated from their babies, so it was a clear sign that there was a problem when Moka would push the baby away when he would begin nursing, Ms. Vacco said.
Once the mother and son were taken to the Animal Care Center for an examination, Ms. Vacco said the baby was mildly dehydrated but otherwise in good health.
Moka, on the other hand, had mastitis -- an infection in her mammary glands. She was given antibiotics to clear up the infection, but all of her milk had dried up so she was unable to nurse her baby, Ms. Vacco said.
In the next few months, the baby will be reunited with his troop once experts deem him strong enough. For the time being, humans must continue to act as mothers, which includes feeding him formula out of a bottle. The formula acts as a substitute for the mother's milk.
The baby spends a few hours per day with his mother, although the pair is separated by a mesh barrier. Otherwise, the protective mother would not let go of her son, Ms. Vacco said.
"Keepers sit in a room adjacent to the bedroom of the gorilla troop, and the baby sits close to the mesh so mom and baby can touch, smell and communicate with each other," zoo spokeswoman Tracy Gray said. "The baby right now isn't ready to go in completely with mom."
Because the zoo has never had the responsibility of rearing a baby gorilla, it called upon experts from Cincinnati for help. Ron Evans, supervisor of primates at the Cincinnati Zoo & Botanical Center, made the trek east to offer advice.
Mr. Evans had his own experiences to share, as he was helping to raise a baby gorilla in Cincinnati at the time. It is unique, he said, that baby gorillas were being raised by humans at three zoos in the same vicinity. In addition to Pittsburgh and Cincinnati, there is one being raised at the Columbus Zoo and Aquarium.
In the last five years, a protocol has been developed by experts to instruct humans on rearing gorilla babies. The goal is to reunite the baby and mother as soon as possible, Mr. Evans said.
By the end of Mr. Evans' visit, it became clear that bragging rights can be applied to gorilla children.
"We were all comparing notes and would say, 'Well, that's great that your baby can do that, but my baby can do this,' " Ms. Vacco joked.
Playing the role of mother gorilla has been a big change for the Pittsburgh staff -- and one that required schedule rearrangements to give the baby 24-hour attention.
Zoo experts are careful to treat the baby gorilla different than a human infant. That means not supporting his head while holding him or swaddling him, which is sometimes a difficult adjustment for keepers who have experience caring for human babies, Ms. Vacco said.
Gorilla keeper Roseann Giambro said she, as well as others who work with the baby, must make gorilla vocalizations to communicate with the infant.
The keepers make grumbles when the baby is eating and can frequently be heard barking at him.
Ms. Giambro said the baby must learn these "gorillaisms" to be able to thrive once he is reunited with his troop. Otherwise he would be very confused and wonder why the other gorillas are "yelling" at him.
Sometimes the gorilla keepers even wear fuzzy vests to better mimic how a real gorilla mother would feel. Ms. Giambro said the vest isn't often worn, though, because it is uncomfortably hot during the summer and sheds.
"We're trying to be gorillas as much as possible, but we do draw a line," Ms. Vacco said.
For now, the baby is doing remarkably well and continues to make progress as he grows, even beginning to eat more vegetables. In fact, Ms. Vacco said he is "very ahead of the curve," most likely due to the four weeks he spent with his mother. Most gorilla babies that are raised by humans have spent very little time with their parents, leading to adjustment problems when they return to the troop permanently.
The baby will be re-introduced to his family when he is able to eat solid foods and when he can be trained to receive his bottle by himself.
Visitors can see the baby gorilla from 10 a.m. to 1 p.m. daily, weather permitting.
Jessica Tully: firstname.lastname@example.org, 412-263-1159 or on Twitter @jessalynn4. First Published July 6, 2013 4:00 AM