Koko, a captive gorilla that learned sign language and raised a kitten, demonstrated to the world the intellectual and emotional capacity of her kind. She died in 2018 at the age of 46, leaving a legacy of children's books, documentaries, scientific papers, and unresolved questions about animal rights.
Koko was a western lowland gorilla, a subspecies of these majestic great apes. Her wild relatives range across several countries in eastern Africa, but they are declining rapidly. These creatures and their very human-like attributes could soon disappear forever.
But it doesn't have to be this way.
What is the Western Lowland Gorilla?
The western lowland gorilla is a critically endangered subspecies of western gorilla.
Its scientific name is Gorilla gorilla ssp. gorilla and its ancestors are thought to have diverged from that of the Cross River Gorilla (Gorilla gorilla ssp. diehli) some 18,000 years ago, according to the International Union for Conservation of Nature (IUCN).
Other gorilla subspecies include the eastern lowland gorilla and the mountain gorilla, the subspecies featured in the 1988 film Gorillas in the Mist.
The western lowland gorilla is slightly smaller than other gorilla subspecies, and has a grey-brown coat and an auburn chest. Their skulls are wider and they have smaller ears and a more pronounced brow, according to the World Wildlife Fund (WWF).
Where is the Western Lowland Gorilla from?
The western lowland gorilla can be found across sections of the Central African Republic, Cameroon, the Republic of Equatorial Guinea, the Democratic Republic of Congo, Gabon and the Republic of Congo.
These apes inhabit dense and remote rainforests, swamps, and swamp forests, according to the WWF.
The largest populations are located in the Republic of Congo (60 percent of the total number) and Gabon (27 percent), Bas Huijbregts, African Species Director at WWF-US, tells Inverse.
What makes the Western Lowland Gorilla so special?
Great apes, including the western lowland gorilla, are our closest living relatives. “We share 98 percent of our DNA with gorillas,” Huijbregts says.
Great apes also play a critical and under-appreciated role in the ecosystems that they inhabit, he says.
“They disperse seeds,” he explains. “Without them and other large-bodied dispersers such as forest elephants, the forest will eventually fail to regenerate.”
How many Western Lowland Gorillas are in the wild?
It is hard to know exactly how many are left because they inhabit remote and dense rainforests, the WWF says. But the IUCN estimates 316,000 left in the wild in 2018.
Despite its critically endangered status, “the western lowland gorilla is the most widespread and numerous of the four gorilla subspecies, [and] accounts for 99 percent of all living gorillas,” Huijbregts says.
Scientists caution that these numbers should not be taken to mean that the population is stable — they are declining. Over the last two decades, the western lowland gorilla’s population has dropped by 60 percent, according to WWF. The IUCN reports a decline of 13 percent since 2013.
Saving this gorilla is not so simple as just removing all the threats to its survival, according to the WWF.
“Even if all of the threats to western lowland gorillas were removed, scientists calculate that the population would require some 75 years to recover,” WWF states on their website.
How many Western Lowland Gorillas are in captivity?
It was difficult to find numbers on western lowland gorillas in captivity. WWF does not keep those numbers, nor does the International Fund for Animal Welfare. The Belfast Zoological Gardens website lists 780 in captivity worldwide. History.com lists 750 gorillas total in captivity and International Gorilla Conservation Programme says most gorillas in zoos are western lowland gorillas. A Journal of Zoology paper from 1988 estimated 600 captive western lowland gorillas worldwide.
What has caused Western Lowland Gorillas' numbers to dwindle?
The greatest threats to the western lowland gorilla are hunting and trade in gorilla meat, habitat degradation and loss, and the spread of disease, Huijbregts says. Ebola and anthrax are deadly diseases that humans can transmit to apes and vice versa.
“In particular, the spread of the Ebola virus has been the main factor causing the massive decline in western gorilla…populations in Gabon and the Republic of Congo, where great ape populations decreased by up to 90 percent in some areas,” Huijbregts says.
Curiously, even mild human respiratory viruses, such as the common cold, can be dangerous to gorillas, too.
How are conservationists working to save the western lowland gorilla?
The WWF is working to promote sustainable development in gorilla habitat, and to combat Ebola by contributing to research and gorilla vaccine development.
Oil palm plantations and open-pit mines are massive threats to gorilla habitat, but creating more protected areas, “following free and prior informed consent of local communities and indigenous peoples,” can change the course for these animals, Huijbregts says. Local communities must actively participate in management of protected areas for programs to be successful, he says.
Most western lowlands gorillas live in forests that are not currently protected from logging, Huijbregts adds. Logging degrades habitat, increases access for poachers, and also increases the chances that disease will be introduced from humans to the gorillas. But gorilla-friendly forestry strategies could hold the answer, Huijbregts says.
The Forest Stewardship Counsil’s (FSC) website says that, in a large FSC-certified logging area in the Republic of Congo, loggers cut an average of one tree per two hectares each year. The area is divided into 30 sections, and only one is subject to harvest each year. That allows 30 years between harvest in each section. Twenty-seven percent of the land area is in permanent reserve. In this certified logging area, “the population of gorillas remains constant. In comparison, the number of gorillas in other areas on the continent are in decline," according to the FSC.
“Working with private sector partners and other stakeholders on protecting these apes within production forests is key,” Huijbregts says.