When renowned zoologist Dian Fossey, the inspiration behind the film Gorillas in the Mist, was murdered in 1985 there were just 250 mountain gorillas left in Africa’s Virunga mountains.
But 27 years on, numbers of the gentle giants have doubled, thanks to a group of doctors that her work inspired.
The Gorilla Doctors, formed as the Virunga Veterinary Center a year after Fossey's death, take care of injured and critically ill gorillas and provide medical treatment and quarantine of orphans, with as many as eight gorillas cared for at any one time.
Quarantine: A young orphaned Gorilla with Dawn Zimmerman (left) and another gorilla doctor in a sanctuary in Rwanda
Starting out with the first Gorilla Doctor - Dr James Foster - the group now employs 16 vets and operates across three countries - the Democratic Republic of Congo, Rwanda and Uganda.
The group rescue gorillas from poacher's snares or when they have been exposed to potentially fatal human viruses, darting the animals with antibiotics or drugging them and operating on the jungle floor.
They have been led for the past 13 years by Dr Mike Cranfield, a faculty member of the Wildlife Health Centre of the University of California Davis and divides his time between Maryland Zoo in Baltimore and central Africa.
Caring: A close up of one of the Gorilla Doctors holding the hand of an adult mountain gorilla as part of the Village of Hope project in Rwanda
Orphan: Isangi with Dr. Martin Kabuyaya of the Gorilla Doctors at Virunga National Parkís Senkwekwe Centre in Rumangabo, Congo
But he admits that there are dangers working with such large animals.
He said: 'If the gorilla screams when darted, there is usually chaos and the silverbacks rush in to protect them.'
His 'closest call' came after darting a mother with a sleeping drug so he could treat her sick infant.
He said: 'Because it was so young I tried to work on it without anaesthetising it but it kept screaming and screaming.'
Treatment: Villagers watch the Gorilla Doctors treating an adult mountain gorilla as part of the Village of Hope project in Rwanda
Emergency treatment: Gorilla doctors treat an adult Mountain Gorilla
Wounded: Dr Magdalena Braum (far right) and Dr Eddy Kambale (far left) remove a bullet from the leg of an orphan Grauer's gorilla confiscated from poachers in Congo, Africa
Gentle: A young gorilla chewing on a branch in the Virunga mountains in Congo. The number of mountain gorillas has doubled since the Gorilla Doctors group was founded in 1986
Playful: An adult Mountain Gorilla seen with a baby in the Virunga mountains in Congo - the gentle giants have doubled in number since 1985 thanks to a group of gorilla doctors
Cute: Two young wild Grauer's gorillas seen playing in Kahuzi-Biega National Park in Congo
source: dailymail