But 10 of the great apes were released back into the wild this week in the Indonesian part of Borneo island by conservation groups.
Due to the coronavirus crisis, which is known to affect apes, the teams used helicopters to move the animals from conservation centres to locations deep in the forest.
The primates are known as the “gardeners of the forest” due to the key role they play in seed dispersal and in maintaining the health of forest ecosystems, but deforestation for agriculture across Indonesia and Malaysia has resulted in rapid habitat degradation and loss.
In total, five male orangutans, a mother with two babies, and two other females were released with assistance from Indonesian conservation agencies.
The Bornean orangutans had all been in captivity before their rescue. Nenuah, a 19-year-old female, was among those released after being repatriated to her homeland from Thailand, according to the Borneo Orangutan Survival Foundation (BOSF).
“Using a helicopter is the best way to transport orangutans during the pandemic,” Denny Kurniawan, BOSF programme manager, told Reuters.
He said it would have taken three days of driving to reach one drop-off area, adding to the risk of Covid-19 transmission.
Due to the orangutans’ susceptibility to human respiratory illnesses, veterinarians wore protective suits and masks during final medical checkups before the apes were moved into the forest.
“Efforts to help curb the spread of the Covid-19 virus have hampered many conservation-related activities,” said Handi Nasoka, acting head of Central Kalimantan’s conservation agency.
Not all rescued orangutans are able to be released into the wild as many have been reared by humans and do not have the skills they would have learned in the wild to allow them to fend for themselves.
But for some, slow rehabilitation at conservation centres mean the humans monitoring them believe they might stand a chance of surviving in the forest.
There are estimated to be just 100,000 Bornean orangutans left in the wild, according to the World Wildlife Fund, with more than half the population having been wiped out over the past 60 years.
Additional reporting by Reuters