Is a Silverback a Species of Gorilla?

Short answerNo. “Silverback” is a life stage, not a species — it means an adult male gorilla, of any subspecies, who has grown the saddle of silver-grey hair across his back and hips at around 12 to 15 years old. There is no such animal as a silverback gorilla in the way there is a mountain gorilla or a western lowland gorilla. Every silverback is one of those; he has simply grown up.

The word gets used as though it named an animal — bigger, rarer and more formidable than an ordinary gorilla. It does not. It is closer in kind to “stallion” than to “zebra”: a description of sex and age, applied to an animal that already has a species name.

No — it's a life stage

As a male gorilla reaches full maturity, the black hair across his back, shoulders and hips is replaced by a distinct silver-grey saddle. The change is gradual, takes place between roughly 12 and 15 years of age, and arrives alongside the rest of adult male development: a pronounced bony crest on top of the skull anchoring enormous jaw muscles, a broad chest, and roughly double the mass of an adult female.

So a silverback is simply a fully grown male. He may be dominant or subordinate, leading a family of thirty or living entirely alone.

The stages a male passes through

Which species has silverbacks

All of them. There are four gorilla subspecies and each produces silverbacks, because each has adult males.

That last point catches people out: the silverback at your local zoo and the silverback in Bwindi are different subspecies, separated by roughly a million years and the Congo basin. We go through why in mountain gorillas in zoos. The mountain gorilla's coat is noticeably longer and denser — an adaptation to cold, wet, high-altitude forest — which is the difference you notice first in the wild.

What a silverback actually does

The dominant silverback is the group. He decides where it feeds, when it moves and where it nests; he mediates disputes between females; he defends against leopards, other silverbacks and perceived threats. Females join or leave a group based largely on their assessment of him.

The reputation for aggression is mostly the result of one behaviour — the display: a build-up of hooting, chest-beating with cupped hands, vegetation-throwing, a sideways run and a final ground-slap. It is loud, it is genuinely alarming at close quarters, and it is overwhelmingly bluff. It exists precisely so that fights do not have to happen.

When a dominant silverback dies without a successor in the group, the family often dissolves entirely — females disperse to other groups, and infants are at risk from incoming males. This is why a single death can matter so much to a population of roughly a thousand animals.

Blackbacks, and why they matter

A blackback is a sexually mature male aged roughly 8 to 12 who has not yet silvered. He faces a choice most people never think about: stay, or go.

Staying means living as a subordinate in a multi-male group, usually his father's, with limited breeding opportunity but the prospect of inheriting the family. Leaving means years alone — solitary males are a real feature of gorilla populations — until he can attract females and found a group of his own.

Multi-male groups matter for trekking, because they are more stable. When the dominant male dies, a subordinate takes over rather than the family fragmenting. Several of Bwindi's habituated families hold more than one silverback, which is why some treks show you three or four adult males in a single sitting.

What you'll see on a trek

Every habituated family has at least one silverback, so seeing one is effectively guaranteed on a successful trek. What varies is how many and how close.

On size specifically, we have a separate piece on how big a silverback gorilla really is — the figures circulated online are frequently captive weights, which run well above wild ones. And for the other great ape confusion, gorilla vs chimpanzee.

We run treks in Bwindi and Mgahinga with permits bought before you travel and the lodge matched to your sector. See how our gorilla treks work, or tell us your dates.

Silverback gorillas: common questions

Is a silverback a species of gorilla? No. Silverback is a life stage, not a species. It describes any adult male gorilla, of any of the four subspecies, that has developed the saddle of silver-grey hair across his back and hips at sexual maturity. Every silverback is a gorilla; not every gorilla is a silverback.

At what age does a gorilla become a silverback? Around 12 to 15 years old. The silver saddle develops gradually across the back, shoulders and hips as the male reaches full physical maturity, alongside a pronounced sagittal crest on the skull and the muscle mass that roughly doubles his weight over a mature female's.

What is the difference between a silverback and a blackback? Age. A blackback is a sexually mature male roughly 8 to 12 years old who has not yet developed the silver saddle. Blackbacks live within the group, often as sons or younger brothers of the dominant male, and either inherit the family, leave to form their own, or spend years as solitary males first.

Can a gorilla family have more than one silverback? Yes, and it is common in mountain gorillas. Multi-male families exist where a dominant silverback tolerates subordinate ones, usually relatives. Bwindi has several such families. Multi-male groups tend to be more stable, because a subordinate can inherit the family rather than it fragmenting when the dominant male dies.

How big is a silverback gorilla? A wild adult male mountain gorilla typically weighs somewhere around 140 to 180 kilograms and stands roughly 1.6 to 1.7 metres upright, with an arm span considerably greater than his height. Females are roughly half the weight. Captive gorillas are often heavier than wild ones and are a poor guide to natural size.

Are silverbacks dangerous to humans? Not in the trekking context. Habituated families are used to a daily hour of human presence and simply carry on. Charges do happen and are almost always bluff — the rule is to stay still, look down and never run. Rangers brief you on this before you enter the forest and the incident rate on regulated treks is very low.