A Cincinnati Zoo & Botanical Garden employee had his thumb partially amputated after a bonobo was attacked during its morning feeding on Friday, the zoo said.
The employee has been stabilized and treated in a hospital, the zoo said in a statement on Friday afternoon.
The bonobo bit through a protective mesh barrier while the primate keeper gave food and medicine to the animals during morning rounds, the zoo said.
It was not clear if the primate made contact with the worker or if the injury came from the barrier.
The zoo emphasized that it happened “behind the scenes” in the Jungle Trails habitat, which was reportedly home to 10 bonobos last year.
“The incident occurred behind the scenes and no other employees, guests or animals were involved or injured,” the report said.
There was no breach and no workers were in the core habitat, the zoo said.
The Jungle Trails habitat was closed that day but would reopen Saturday, a zoo spokesperson said.
“The zoo is investigating the details to understand what led to the incident,” the institute said in a statement.
The zoo has not revealed which animal was involved in the incident.
Gilda, an 18-year-old bonobo, gave birth to a boy at the facility on September 8, the zoo said. On September 30, the zoo posted a video of the pair making their first public appearance in their habitat.
The bonobo is a primate closely related to chimpanzees.
The International Union for Conservation of Nature and Natural Resources lists the bonobo as an endangered species with a population declining due to development, civil unrest and mining in its native country, the Democratic Republic of Congo.
The nonprofit Bonobo Conservation Initiative said reliable population estimates are difficult to come by. “There are only 15,000 bonobos left today,” the website says.
Bonobos, often organized around female leadership, are considered more peaceful, intelligent and empathetic than other primates. Because they are the last great apes discovered by humans (they were officially designated as a species in 1929), researchers are still making discoveries and hope to make more.
One of the most important possible insights is what bonobos can teach researchers about humans. The primates share 98.7% of their DNA with humans, making them our closest relative in the animal kingdom, according to the World Wildlife Fund.
This article was originally published on NBCNews.com