Chewing plants is assisting veterinarians in providing personalized health care to wild, endangered mountain gorillas in East Africa. A mountain gorilla walks through the forest of East Africa’s Virunga Volcanoes conservation area. It comes to a halt at a piece of wild celery, sits down, and begins to chew. It extracts the fleshy, juicy bits from the fibrous threads of the vegetable with its teeth, then drops the chewed stalk on the ground and ambles away.
Minutes later, wildlife veterinarians on the scene write down the gorilla’s name and retrieve the saliva-drenched plant, which contains vital information about the gorilla’s health. This simple, noninvasive tool of a chewed plant is helping Gorilla Doctors – who know each gorilla by name – provide personalized health care to wild, endangered mountain gorillas living in Rwanda, Democratic Republic of Congo (DRC) and Uganda.
The technique was used by scientists from the University of California, Davis, to rule out the presence of human herpesviruses among the region’s mountain gorillas. Their findings were published in the American Journal of Primatology.
Gorilla Doctors is a collaboration between the Karen C. Drayer Wildlife Health Center, part of the UC Davis School of Veterinary Medicine, and the Mountain Gorilla Veterinary Project. The program monitors mountain gorilla health and provides veterinary care to injured and ill gorillas.
We were able to complete this study entirely with chewed plants. We were able to collect specimens from every known habituated mountain gorilla in Uganda and Rwanda as a result of this. This demonstrates that we can monitor gorillas and possibly other primate species over time, noninvasively, at the individual level, and help answer conservation questions.
Tierra Smiley Evans
Individual care
While a human herpesvirus may cause only a cold sore in humans, it could be far more dangerous if introduced to gorillas or other species. The study found no evidence of human herpesvirus infection among the free-roaming gorillas after extracting DNA from the discarded plants and screening them for orally shed pathogens.
“We were able to complete this study entirely with chewed plants,” said Tierra Smiley Evans, research faculty with WHC and One Health Institute at UC Davis. “We were able to collect specimens from every known habituated mountain gorilla in Uganda and Rwanda as a result of this. This demonstrates that we can monitor gorillas and possibly other primate species over time, noninvasively, at the individual level, and help answer conservation questions.”
Staying vigilant
Gorilla trekking is popular in this area, and the wild gorillas are used to humans. While gorilla tourism encourages habitat conservation, it also necessitates a high level of care to prevent people and gorillas from contracting diseases.
The study’s discovery that human herpesviruses have not spread indicates that guidelines used by Gorilla Doctors and gorilla management authorities to limit the distance between humans and gorillas in the park are assisting in the prevention of disease spread. It also serves as a reminder to remain vigilant in order to prevent new viruses from infiltrating the population.
“Gorilla Doctors research has proven that human viruses cause respiratory disease in endangered mountain gorillas,” said co-author Kirsten Gilardi, DVM, executive director of the Gorilla Doctors and director of the WHC at UC Davis. “Dr. Evans’ research findings that human herpesviruses were not detected in gorilla saliva was reassuring. It’s further evidence that park rules for gorilla visitation, like wearing face masks and keeping a minimum distance of 23-33 feet, are effective in reducing the risk of transmission of human diseases to mountain gorillas.”
Gorilla IDs
Chewed plant analysis is a relatively new tool for Gorilla Doctors to provide personalized care to this endangered species. Face time, of course, is also important, and the Gorilla Doctors and rangers know individual gorillas by sight. Such recognition is greatly aided by the wrinkles above each gorilla’s nose. Mountain gorillas have distinct noseprints used by veterinarians and rangers to identify them, much how fingerprints are used to identify people.
When observing mountain gorillas, Evans claims that the personalities and dramas of gorilla life become immediately apparent. Evans recalls seeing a young male gorilla while collecting samples for her Ph.D. studies a decade ago.
“He was in his adolescence and was constantly causing problems. He was also my favorite because he was a fascinating, inquisitive individual” She stated. “I recently returned, and there he is, 10 years later, this calm, big silverback with babies crawling all over him. ‘That’s Kabukojo,’ someone said. ‘You’re kidding me!’ I exclaimed. We’d all grown older and changed.”
