Acacia, an 18-year-old gorilla at the North Carolina Zoo, is pregnant. Her keepers and the zoo veterinarians expect her to give birth sometime in early summer. A female gorilla’s gestation period is similar to that of humans – about 8 1/2 months – but officials cannot be more specific about a birth date because they don’t know exactly when Acacia got pregnant. The father is Nkosi, a 22-year-old silverback who moved to the zoo in Asheboro from the Columbus, Ohio, Zoo in 2008. He has fathered two other gorillas born at the N.C. Zoo in 2011 and 2012. Both are male and were the first gorillas born there in 23 years. The gorillas are under the daily care of keepers assigned specifically to the gorillas; medical monitoring is done by the zoo veterinarians, who are responsible for all the animals at the zoo – not just gorillas.
Dr. Michael Loomis, DVM, is head veterinarian at the zoo. Aaron Jesue is a Keeper II. He and another keeper, supervised by Animal Management Supervisor III Chris Goldston, provide daily care for the gorillas.
Q: How do you know if a gorilla is pregnant?
“We use the same pregnancy test kit used for humans,” Loomis said. “The hormones in a gorilla’s urine are similar to those in humans.” It is hard to tell if a gorilla is pregnant just by looking because they naturally have large stomachs. Aside from this, Loomis said, “Gorilla pregnancies are remarkably similar to humans’.”
Once tests show a gorilla definitely is pregnant, she is monitored with an ultrasound probe. In this, female gorillas are not as compliant as most human women. Acacia has been trained to present – placing her stomach against a mesh panel in the window at the rear of the exhibit area so the ultrasound probe can reach in next to her stomach. But once when the probe was placed through the mesh, Acacia grabbed it and broke it.
Since then, according to Jesue, they developed strategies to keep Acacia from breaking another probe. “We trained her to keep her hands higher on the mesh, so she can’t reach the probe as fast,” he said. And the new probe is fitted inside a sleeve. “If she grabs it now,” Jesue said, “we can pull the probe away before she lets go of the sleeve if we are fast enough. We need to move fast.”
This strategy is important because the probes cost thousands of dollars and the zoo cannot afford repeated replacements. “We want to be sure we are taking care of this important and expensive piece of equipment,” Goldston said.
Q: What do you feed pregnant gorillas?
“We try to have them on a diet for good health,” Loomis said. This, too, is similar to what is considered a healthful diet for humans: low in sugar and starch, high in fiber, leafy greens and vegetables, with a little bit of fruit.
It is also the same diet fed to all gorillas at the zoo, though Jesue said the female’s diet is increased 10 percent in volume when she is pregnant. Training treats for all gorillas, pregnant or not, include carrots, green beans and kiwi fruit, except for the silverback father, Nkosi. “He enjoys kiwis too much,” Jesue said. “He throws up so he can enjoy it again. But he still enjoys the other treats.”
Q: When the gorilla goes into labor, how is the actual birth managed?
The zoo has no special birthing areas or delivery procedures, though the holding and exhibit areas are kept clean. “The goal is to keep everything normal for the female. We don’t separate her from the rest of the troop,” Loomis said, “though we do keep a watch to make sure nothing goes wrong.” Gorillas tend to deliver without protracted labor and usually need no assistance. Often during labor they give no indication of being uncomfortable, so the process is not obvious. The keepers may find the mother with the troupe and with her baby, before they are aware she was giving birth.
Q: What kind of postnatal care do you give the babies?
It depends on the mother. “We do like to get our hands on the infant, but if the mother is nervous about separation, we wait until time for her next periodic health examination and vaccinations, when she is anesthetized. We check her baby then,” Loomis said. This may be six to eight months after the birth. The baby can be examined and returned to its mother before she rouses from the anesthesia so she will not know it was gone.
Keepers observe the mother with her baby to make sure she is nursing and holding it correctly, not smothered in her fur, Jesue said.
Q: Female gorillas are big animals. Are they more dangerous when they are pregnant or after birth?
They may be more agitated with the presence of another female or the silverback (adult male), Jesue said. “But if he shows any signs of bothering the mother, the other females go after the silverback. Ordinarily he is the dominant gorilla, but the females will protect the new mother.”
Q: Aside from nursing, what do baby gorillas eat and when do they start on solid food?
There’s no special protocol for feeding the babies. “They eat what the adults eat. They start experimenting when they are young and learn by watching other adults in the troop,” Loomis said. “They manage pretty doggone well, I think.”