A gorilla is a great ape, not a monkey, and the largest primate on Earth. Gorillas live in the forests of central Africa, eat mostly plants and share about 98% of their DNA with humans. Only about 250 Cross River gorillas remain, but mountain gorillas have climbed back to about 1,063.
Gorilla quick facts
- Gorillas are apes, not monkeys. The quickest test is the tail: monkeys have one, apes do not.
- They are the largest primates alive, with males reaching 195 kg and an arm span of up to 2.6 m.
- Gorillas share roughly 98% of their DNA with humans, making them our closest relatives after chimpanzees and bonobos.
- Their diet is almost entirely leaves and stems. An adult male can eat up to 30 kg of plants a day.
- Mountain gorillas were moved from Critically Endangered to Endangered in 2018 after their numbers grew to about 1,063.
A silverback gorilla can weigh as much as three grown men, with a strength no human athlete could match. Yet he spends roughly half his waking life sitting quietly in one spot, eating leaves. That gap between how gorillas look and how they behave is the most interesting thing about them. Almost everything people think they know about gorillas sits on the wrong side of it.
First things first: a gorilla is not a monkey
This gets muddled constantly, including by books and websites that ought to know better. Gorillas are apes, and apes and monkeys are different branches of the primate family.
The quickest way to tell them apart is to look for a tail. Monkeys have one. Apes do not, and that includes gorillas, chimpanzees, bonobos, orangutans, gibbons and, for that matter, you. Apes are also generally larger, with bigger brains for their body size. They can swing their arms in a full circle at the shoulder. That is why an ape can hang and swing from a branch in a way a monkey cannot.
Gorillas are the largest primates alive anywhere on Earth, and after chimpanzees and bonobos they are our closest living relatives. We share around 98% of our DNA with them. Scientists confirmed this in 2012, when they finished reading the gorilla genome from a western lowland gorilla named Kamilah at San Diego Zoo.
The basics
| What they are | Great apes, the largest primates on Earth |
| Species | Two: the eastern gorilla and the western gorilla |
| Subspecies | Four, and they are in very different amounts of trouble |
| Where | Forests of central Africa, split either side of the Congo River |
| Size (males) | 1.4 to 1.8 m tall, 136 to 195 kg |
| Size (females) | Roughly half the weight of a male |
| Diet | Almost entirely plants: leaves, stems, shoots, some fruit |
| Group | A troop, led by one silverback |
| Baby | An infant, born after about 8.5 months |
| Lifespan | 35 to 40 years wild, over 50 in zoos |
The four kinds of gorilla
There are two species, and each splits into two subspecies. This matters more than it sounds. Their situations are wildly different, and lumping them together hides the most important thing happening to gorillas right now.
| Subspecies | Where | Roughly how many |
|---|---|---|
| Western lowland gorilla | Cameroon, Gabon, Congo, Central African Republic | Around 316,000 — nearly every gorilla you have seen in a zoo is one of these |
| Grauer’s gorilla (eastern lowland) | Eastern Democratic Republic of the Congo | About 3,800, down from roughly 17,000 in the 1990s |
| Mountain gorilla | Volcanic mountains of Rwanda, Uganda and DR Congo | About 1,063, and rising |
| Cross River gorilla | A small patch of the Nigeria–Cameroon border | Around 250 to 300, the rarest great ape on Earth |
The one piece of genuinely good news
In the early 1980s there were fewer than 300 mountain gorillas left. Most experts at the time expected them to be gone before the century ended. Dian Fossey, who studied them in Rwanda and was murdered in 1985, thought so too.
They are still here. The most recent full count put the mountain gorilla population at 1,063. In 2018 the IUCN moved them from Critically Endangered down to Endangered. That downgrade sounds small, but it is enormous. It is one of very few times a great ape has moved in the right direction on that list.
It happened because of unglamorous, patient work. Rangers patrol the parks and remove snares, often at real personal risk. Vets treat injured animals in the wild. Tourists pay large sums to spend one carefully controlled hour watching a family group. That money gives local communities a solid reason to want gorillas alive. None of it is finished, and 1,063 is still a tiny number, but it worked.
Every other gorilla is still going the wrong way. Grauer’s gorillas have lost around 80% of their population in a single generation, mostly because of war, mining and hunting in eastern Congo. Cross River gorillas are down to a couple of hundred animals scattered across a handful of hilltops.
The Four Kinds of Gorilla
- Western lowland gorilla — Almost every gorilla you have seen in a zoo
- Grauer's gorilla — Lost more than three-quarters of its numbers in one generation
- Mountain gorilla — Lives on volcanic mountains in Rwanda, Uganda and DR Congo
- Cross River gorilla — The rarest great ape, on the Nigeria–Cameroon border
How big is a gorilla, really?
An adult male stands about 1.4 to 1.8 metres tall when upright. He weighs between 136 and 195 kg, comfortably more than twice an average adult human. His arms span wider than he is tall, sometimes reaching 2.6 metres from fingertip to fingertip. Females are roughly half his weight, and the size gap between males and females is one of the largest of any primate.
The heaviest wild gorilla ever recorded was a silverback shot near Ambam in Cameroon that weighed 267 kg. Gorillas in zoos can grow heavier still, because they get more food and do less walking.
Their proportions are the opposite of ours. A gorilla’s arms are far more powerful than its legs. Its belly is wider than its chest, because it needs an enormous gut to break down all those leaves. And it walks on its knuckles rather than its palms. They have 32 teeth, the same as us. Like us, they get baby teeth first and adult ones later.
How a Gorilla Is Built
- Arms — Far more powerful than its legs
- Belly — Wider than its chest, to hold a huge gut for digesting leaves
- Knuckles — What it walks on, instead of its palms
- Teeth — 32 of them, the same number as ours
- A silverback's arm span — Wider than he is tall
What gorillas actually eat
Leaves, mostly. Also stems, shoots, bark, pith and a certain amount of fruit, depending on which kind of gorilla and what time of year it is. An adult male can put away 18 to 30 kg of plants in a day. That takes hours. So a gorilla’s daily routine is basically eat, rest, eat, rest, sleep.
Mountain gorillas eat the least fruit, because not much grows at their altitude. They get nearly all their water from the plants they chew, rather than from drinking. Western lowland gorillas eat the most fruit and will also break open termite mounds and ant nests for a bit of protein.
One thing they do not eat is bananas. Wild gorillas almost never encounter them, and the banana-loving ape is a cartoon invention rather than anything from the forest.
Life in a troop
Gorillas live in family groups called troops, usually somewhere between five and thirty animals, built around a single adult male called a silverback. He gets the name from the saddle of silver-grey hair that grows across his back and hips once he passes about twelve years old. Younger adult males, aged roughly eight to twelve, are called blackbacks and have not developed it yet.
The silverback decides where the troop goes, when it stops, where it sleeps, and what happens when something threatens it. He does not usually do much childcare, but infants are drawn to him anyway. He will step in to break up squabbles among the youngsters.
Every gorilla old enough to be independent builds a fresh nest every night. It weaves branches and leaves into a rough bowl on the ground, or sometimes in a tree. It sleeps there once and leaves it the next morning. Infants share their mother’s nest until they are about three. Field researchers count abandoned nests to work out how many gorillas live in an area. That is how most population surveys are done.
What the chest beating is really for
A silverback rears up, cups his hands and drums on his chest, and the sound carries over a kilometre through dense forest. Films treat this as the moment before an attack. It is closer to the opposite: a way of settling the question without anybody fighting.
In 2021, researchers working in Rwanda published a study of wild silverbacks and their chest beats. They found the sound is honest. Larger males produce lower-pitched beats, and the pitch reliably tells other gorillas how big the drummer is. A rival hearing a deep chest beat from behind the trees knows he would lose, and can leave without either animal getting hurt. Cupped hands, rather than flat palms, are what make the sound so deep and carrying.
Babies and growing up
A gorilla pregnancy lasts about 257 days, just under nine months, which is remarkably close to ours. Almost always a single infant is born, weighing around 2 kg, roughly half what a human newborn weighs, and completely helpless.
For the first few months the infant clings to its mother’s chest and feeds about once an hour. By around four months it can ride on her back. At three years it starts sleeping in its own nest. A female usually does not have another baby until the first is around four. That slow pace is part of why gorilla numbers recover so gradually. A female might raise only three or four surviving young in her whole life.
Growing Up Gorilla
- Born A helpless infant is born, weighing around 2 kg.
- Clinging It clings to its mother's chest and feeds about once an hour.
- Riding After a few months, it starts riding on its mother's back.
- Its own nest At about three years old, it starts sleeping in a nest of its own.
- Blackback A young adult male, aged about eight to twelve, is called a blackback.
- Silverback Silver-grey hair grows across his back, and he may lead a troop.
How clever are they?
Clever enough to surprise the people who study them. Wild gorillas use tools, though less often than chimpanzees do. In one famous observation in the Congo, a female picked up a branch and used it to test how deep a pool of water was before wading in. Another used a log as a bridge.
The best-known gorilla in the world was Koko, born at San Francisco Zoo in 1971. She was taught a modified version of American Sign Language and used more than a thousand signs. She died in 2018. Researchers still argue about how much of what Koko did was real language rather than clever imitation. The honest answer is that nobody is completely sure.
Every gorilla has a unique pattern of wrinkles on its nose. Researchers photograph noses to tell individuals apart, much as police use fingerprints.
Things people get wrong about gorillas
- “Gorillas are monkeys.” They are apes. Monkeys have tails and gorillas do not.
- “All gorillas are critically endangered.” Both species are, but the mountain gorilla was moved down to Endangered in 2018 after its numbers grew. Saying they are all equally doomed erases the one conservation success story gorillas have.
- “There are only 880 mountain gorillas left.” That figure is a decade out of date. The current count is about 1,063.
- “Unlike chimpanzees, gorillas build nests.” Chimpanzees build nests too, every night, as do orangutans and bonobos. Nest-building is something all the great apes do.
- “Gorillas are aggressive.” They are among the calmer great apes. Almost all the frightening behaviour, including the chest beating, is display designed to avoid a fight rather than start one.
- “Colo was the oldest gorilla ever.” Colo died in 2017 aged 60, and she held the record at the time. Fatou, at Berlin Zoo, has since become the oldest gorilla on record, and she turned 69 in April 2026.
- “Gorillas love bananas.” Wild gorillas rarely see a banana in their lives.
- “King Kong.” No gorilla has ever been anywhere near that size, and gorillas do not climb buildings, eat people, or roar. Their loudest normal sound is a belch, used to tell the rest of the troop that everything is fine.
Why gorillas are in trouble
Four things, roughly in order of damage done.
Habitat loss is the biggest. Forest is cleared for farms, timber and mining. Gorillas end up in shrinking islands of woodland, too small and too far apart for them to move between.
Hunting is next. Gorillas are killed for bushmeat, and snares set for other animals catch them by accident. That is why so much ranger work is simply walking the forest, pulling wire loops out of the ground.
Disease is the one people forget. Because gorillas are so genetically close to us, they catch our illnesses, and they have no resistance to them. Ebola outbreaks have killed thousands of western lowland gorillas. A human cold can kill a mountain gorilla. That is why tourists must stay several metres back, and anyone feeling unwell is turned away at the gate.
War covers the rest. Long conflicts in eastern Congo have made whole regions impossible to protect. That, more than anything else, is what happened to Grauer’s gorillas.
Twelve facts worth remembering
- Every gorilla has a unique nose print, used by researchers exactly like a fingerprint.
- Gorillas cannot swim and will go a long way round to avoid deep water.
- They build a brand new bed every night and never sleep in it twice.
- A contented gorilla belches. It is a genuine signal meaning roughly “all is well here”.
- Chest beating tells other gorillas how big you are, and bigger males make a deeper sound.
- Gorillas share about 98% of their DNA with humans.
- A silverback’s arms can span 2.6 metres, wider than he is tall.
- Mountain gorillas get almost all their water from the plants they eat.
- Fatou, at Berlin Zoo, is the oldest gorilla in recorded history and turned 69 in 2026.
- Gorillas can run on two legs, but only for a few metres.
- Cross River gorillas number only a couple of hundred, making them the rarest great ape alive.
- The mountain gorilla is one of the very few great apes whose numbers are going up.
Did you know? Every gorilla has a unique pattern of wrinkles on its nose. Researchers photograph gorilla noses to tell individuals apart, in much the same way police use fingerprints.
Gorillas: Fact or Myth?
- Wild gorillas love eating bananas.
- Every gorilla has a unique nose print.
- Gorillas are the only great apes that build nests.
- Gorillas cannot swim.
- When a silverback beats his chest, he is about to attack.
- A contented gorilla belches to tell the troop that all is well.
- A gorilla sleeps in the same nest every night.
- Gorillas can catch human illnesses, even a cold.
Try it
Look up photographs of a gorilla and a baboon side by side and find three differences. Start with the tail, which is the one that tells you which is an ape and which is a monkey.
Knowledge check
Is a gorilla a monkey or an ape, and how can you tell?
Show answer
A gorilla is an ape. The simplest test is the tail: monkeys have tails and apes do not. Chimpanzees, orangutans, gibbons and humans are all apes too.
Are all gorillas critically endangered?
Show answer
Not quite. Both gorilla species are listed as Critically Endangered, but the mountain gorilla was moved down to Endangered in 2018 after conservation work grew its population to about 1,063. It is one of the few great apes whose numbers are rising.
Frequently asked questions
Is a gorilla a monkey or an ape?
A gorilla is an ape, not a monkey. The simplest test is the tail: monkeys have one and apes do not. Gorillas, chimpanzees, bonobos, orangutans, gibbons and humans are all apes.
How many gorillas are left in the world?
There are around 320,000 gorillas in total, but almost all are western lowland gorillas. There are roughly 3,800 Grauer’s gorillas, about 1,063 mountain gorillas and only around 250 Cross River gorillas.
What do gorillas eat?
Gorillas eat almost entirely plants: leaves, stems, shoots and some fruit. Some also eat ants and termites. An adult male gorilla can eat up to 30 kg of plants a day.
Why is a male gorilla called a silverback?
An adult male gorilla is called a silverback because a patch of silver-grey hair grows across his back and hips from about twelve years old. Younger adult males without it are called blackbacks.
How strong is a gorilla?
A gorilla is far stronger than any human, though the exact figures quoted online are mostly invented. A silverback weighs up to 195 kg, with arms built to haul his whole body weight through the trees.
Are gorillas dangerous?
Gorillas are rarely dangerous. They are shy animals that avoid confrontation, and a charging silverback is almost always bluffing to make an intruder back off. Human illnesses are a bigger danger to gorillas than gorillas are to people.
How long do gorillas live?
Gorillas live around 35 to 40 years in the wild and more than 50 in zoos. The oldest ever recorded is Fatou at Berlin Zoo, who reached 69 in April 2026.
Sources
- IUCN Red List: mountain gorilla — the 2018 move from Critically Endangered to Endangered.
- WWF: mountain gorilla — the population figure of about 1,063.
- PLOS ONE: catastrophic decline of Grauer’s gorilla — the roughly 80% population loss in one generation.
- Scientific Reports: chest beats as an honest signal of body size — why bigger silverbacks produce deeper chest beats.
- Nature: insights into hominid evolution from the gorilla genome — the DNA comparison with humans.
- The Dian Fossey Gorilla Fund — long-running field research on wild mountain gorillas.
Gorilla Final Challenge
- What does a deep chest beat tell other gorillas?
- How do researchers usually count the gorillas living in an area?
- Where do mountain gorillas get nearly all their water?
- What did one female gorilla in the Congo use a branch for?
- What was Koko, the gorilla born at San Francisco Zoo in 1971, famous for?
- Why do gorilla numbers recover so slowly?
- What is the biggest threat to gorillas?
- How does gorilla tourism help mountain gorillas?
