- The mountain gorilla is the only species whose population is increasing
Mountain gorillas are classified as ‘endangered’ - there are an estimated 1,000 mountain gorillas in the wild according to the latest census (which is done every 5-10 years). Despite this status, the number of mountain gorillas is showing growth - the only of the three gorilla subspecies to be increasing in population. Gorillas are human’s closest living relatives after chimpanzees and bonobos.
They are the largest living primate, although Gigantopithecus (a relative of the orangutan and probably the inspiration for the mythic yeti) was historically larger and the now extinct Archaeoindri from Madagascar came close. Despite famous gorillas in the media like King-Kong, Donkey Kong, Gorilla Grodd in DC Comics and other fictional ones being portrayed as so big, a 6-foot man in real life stands taller than your big gorilla (but unlikely to be as heavy). They stand at 5’11 and weigh 200 kilograms and so, are shorter than a tall man when they walk on all fours – shorter than most basketball players!
- Gorillas have complex social structures and even a ‘language’ of their own
Gorillas live in groups with the male silverback leading many females and babies. The young males are pushed out shortly after puberty and form bachelor troops. They may become silverbacks of their own packs in time. They have 16 different cries which humans can mimic. When you go for the gorilla walk in Uganda or Rwanda, you can see the tour guides mimic these, especially the friendly greeting: literally saying “hello” as one does to a friend. John Makombo, Program Director for Uganda Wildlife Authority said that when a silverback dies, the new silverback will not kill the babies of the previous, unlike the lions that kill the cubs of the previous leader when they takeover a pride. They also have a unique reaction like human laughter.
- They are vegetarians and do not harm humans unless threatened
They are ‘gentle giants’ but can hurt you if you try to harm them. According to tour guide Gerad Ndahura, the forest-dwelling Batwa pygmies call them Avanyamuzari (literally relatives) and they are called Engagi in their language. Different tribes have different names and myths about it. Nowadays, they are killed for meat in Uganda and Rwanda because of Congolese refugees coming in, but that is only since the last 50 years. Chimps and orangutans eat no meat. Gorillas have been seen eating insects such as erisyamuni, a local Kiga name for a type of black ant, although they are the most vegetarian of the great apes.
Gorillas have also been observed eating eucalyptus when they have indigestion - a plant introduced from Australiainto Africa. According to Ugandan wildlife Authority gorilla tracker Ivan Mwasheramanu, gorillas emit a musk to deter intruders and so, any bad smell is called engagi in the Kiga language (same as Batwa). The Kiga and the Batwa have folklore about gorillas. The Bafumbira, Kinyarwanda and Kirundi call it ingagi. Other tribes such as the Songye in the Congo may have the same word for gorilla and chimpanzee (soko). On the other hand, African groups such as the Maasai or the Kalenjin will not have a specific word for gorilla because they never interacted with them.
- Gorillas use tools
Although tool use has been observed, they do not use them as much as chimps and orangutans do. Ugandan Zoologist Dr. Panta Kasoma said that this could possibly be an adaptation since they are more vegetarian than the other two and so can pick their food more readily in nature and do not need tools much. However, baby gorillas have been observed dismantling poachers’ trap; they have good hands! In addition, gorillas in captivity can do paintings and use sign language to communicate.
In the wild, they use branches and leaves to scare off other animals. They have been observed using the hair on the back of their hand to lap up drinking water – hardly counts as a tool as such. Baby gorillas are curious and will pull colourful items such as shoes, clothing, or dyed hair that they see on tourists. A baby in Rwanda once picked up a glove which a Luxembourgish tourist dropped, and the angry silverback confiscated it and threw it back at the tourist.
- Gorillas and Chimpanzee live in the same forests but they usually avoid each other
Lara Southern, primatology PhD student at Osnabruck university said “most encounters are very brief and the two species seem to demonstrate mutual avoidance”. Chimpanzees spend more time on trees than the ground-dwelling gorilla. Southern said that “they occupy different sub-niches to reduce competition”.
Southern was the first author of the study that saw the first gorilla-chimpanzee conflict in Gabon. However, she suggests that this does not happen among the two different apes always, citing an occurrence in the Republic of the Congo (ROC) where “Gorillas and chimps had been observed co-feeding in the same tree and two juveniles of the different species were even seen playing with each other”. The lowland gorilla subspecies here is slightly different from the mountain gorilla, with which conflict has not been observed.
Prof Robert Bitahiro from the Institute of Tropical Forest Conservation while discussing the mountain gorilla behavior said that “they simply avoid each other in Uganda. The gorilla is a big animal and in a large group, so most animals would rather avoid them and vice versa”.
Although gorillas are bigger, chimpanzees are more aggressive and tend to hunt prey due to a more omnivorous diet and can harm young gorillas that have strayed away, as seen in Gabon. A similar phenomenon in Sri Lanka occurs when two native monkey species have conflict: the smaller macaque (rilawa) dominates over the larger langur (vanthura) simply because it is more aggressive, according to German-born primatologist Dr. Wolfgang Dittus who is based in Sri Lanka.
Mountain Gorillas can be seen in Uganda, Rwanda and the Democratic Republic of the Congo.