---
title: "What the sources say about the Mountain Gorilla | AnimalTracks.wiki"
description: "44 claims from the Mountain Gorilla profile, each beside the words of the source that backs it."
image: "https://animaltracks.wiki/images/animals/mountain-gorilla-1.webp"
canonical: "https://animaltracks.wiki/animals/mountain-gorilla/sources/"
---

# What the sources say about the Mountain Gorilla (*Gorilla beringei beringei*)

> 44 claims from the Mountain Gorilla profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Mountain Gorilla](https://animaltracks.wiki/animals/mountain-gorilla/)

## Wright et al. (2021). Chest beats as an honest signal of body size in male mountain gorillas (Gorilla beringei beringei). Scientific Reports.

https://doi.org/10.1038/s41598-021-86261-8

| The page says | The source says |
| :--- | :--- |
| a chest beat heard more than a kilometer away | This multimodal long-distance signal, which can be heard over 1 km away |
| A chest-beat drumroll that can be heard more than a kilometer away, pitched lower the bigger the male beating it | This multimodal long-distance signal, which can be heard over 1 km away ... The chest beat of larger males comprised significantly lower peak frequencies than smaller males |
| he usually rises onto two legs and beats his chest with cupped hands, producing a drumroll that can be heard more than a kilometer away | Chest beating is performed when individuals usually rise bipedally and rapidly beat their chests with cupped hands in rapid succession, producing an impressive drumming sound ... which can be heard over 1 km away |
| Researchers who recorded six wild silverbacks in Rwanda's Volcanoes National Park | Volcanoes National Park, Rwanda ... six adult males from two social groups |
| found that bigger males beat at a lower pitch than smaller ones | The chest beat of larger males comprised significantly lower peak frequencies than smaller males |
| Across the six, the average peak pitch was about 639 Hz | The mean peak frequency per male was 638.9 Hz (note: 639 rounds 638.9) |
| That makes the chest beat an honest signal | we conclude that the gorilla chest beat is an honest signal of competitive ability |
| the sound itself carries information about how big the drummer is | we have demonstrated that chest beats reliably convey the body size of the emitter |
| Chest beats are thought to help males judge a rival's fighting ability, though the researchers say future studies still need to show that listening gorillas use it | future studies need to show that receivers actually attend to this information. Gorilla chest beats are thought to play a key role in male–male competition allowing individuals to assess the fighting ability of competitors |
| The bigger the silverback, the lower the pitch of his chest beat | The chest beat of larger males comprised significantly lower peak frequencies than smaller males |
| Researchers call that an honest signal | we conclude that the gorilla chest beat is an honest signal of competitive ability |
| it can be heard more than a kilometer away | which can be heard over 1 km away |
| Silverbacks usually rise onto two legs and slap cupped hands against their chest, producing a drumroll that can be heard more than a kilometer away | Chest beating is performed when individuals usually rise bipedally and rapidly beat their chests with cupped hands in rapid succession, producing an impressive drumming sound ... which can be heard over 1 km away |
| Recordings of six wild silverbacks in Rwanda | Volcanoes National Park, Rwanda ... six adult males from two social groups |
| bigger males beat at a lower pitch than smaller ones, so the sound carries honest information about a male's size | The chest beat of larger males comprised significantly lower peak frequencies than smaller males |
| Chest beats are thought to help males size up rivals, though researchers still need to show that listening gorillas actually use that information | future studies need to show that receivers actually attend to this information. Gorilla chest beats are thought to play a key role in male–male competition allowing individuals to assess the fighting ability of competitors |
| usually rises onto two legs and beats his chest with cupped hands into a drumroll heard more than a kilometer away | Chest beating is performed when individuals usually rise bipedally and rapidly beat their chests with cupped hands in rapid succession, producing an impressive drumming sound ... which can be heard over 1 km away (note: vibe.reason (#692/#693)) |
| The bigger the male, the lower the pitch | This multimodal long-distance signal, which can be heard over 1 km away ... The chest beat of larger males comprised significantly lower peak frequencies than smaller males (note: vibe.reason (#692/#693)) |

## Elgart-Berry (2004). Fracture toughness of mountain gorilla (Gorilla gorilla beringei) food plants. American Journal of Primatology.

https://doi.org/10.1002/ajp.20021

| The page says | The source says |
| :--- | :--- |
| a study of food plants from Bwindi Impenetrable and Mgahinga Gorilla National Parks measured its fracture toughness at up to 8.2 kilojoules per square meter, tougher than the leaves and bamboo gorillas also eat | Samples of 44 food plants from Bwindi-Impenetrable National Park (BINP) and Mgahinga Gorilla National Park (MGNP) were tested ... Tree barks were the toughest food items (varying from 0.23 to 8.2 kJ/m2) ... The toughness of leaves and fruit was negligible compared to that of bark. The toughness of bamboo was low in comparison to the toughest food items. |
| The researchers suggest that tough bark, pith, and stems may be key reasons mountain gorillas evolved such robust jaws and faces | the prominent toughness of bark, pith, and stems may be key factors in the evolution of orofacial robusticity in mountain gorillas |

## McFarlin et al. (2026). Variation in body size growth trajectories between ecologically distinct mountain gorilla populations. Proceedings of the Royal Society B: Biological Sciences.

https://doi.org/10.1098/rspb.2025.2227

| The page says | The source says |
| :--- | :--- |
| A 2026 study comparing gorillas from Bwindi and the Virungas found that males from the two places end up almost the same adult size, while Bwindi females stay smaller and keep growing for longer | Bwindi females attained a smaller adult size than Virunga females, despite continuing their growth over a longer duration. Population differences in male adult size were minimal (note: 2026 is the reference's publication year) |

## Gorilla beringei (eastern gorilla). Animal Diversity Web, University of Michigan, 2001.

https://animaldiversity.org/accounts/Gorilla_beringei/

| The page says | The source says |
| :--- | :--- |
| In the Virunga volcanoes, which separate the Democratic Republic of Congo from Rwanda and Uganda, they mostly live in montane cloud forest, and sometimes climb as high as 4,000 meters into afro-alpine meadows where nights turn subfreezing and there is little food to forage | are found in the Virunga volcanoes that separate the Democratic Republic of Congo from Rwanda and Uganda. ... Mountain gorillas inhabit the montane cloud forest of the Virunga range. Occasionally they go into the afro-alpine meadows (4,000 m) where temperatures are subfreezing at night and there is little suitable food to forage on. |
| Their hair is longer than other gorillas' | Mountain gorillas differ from other gorillas in having longer hair |
| Mountain gorillas have longer hair than other gorillas | Mountain gorillas differ from other gorillas in having longer hair |
| They mostly live in the montane cloud forest of the Virunga volcanoes, but sometimes climb to 4,000 meters into afro-alpine meadows, where nights drop below freezing and there is little to eat | Mountain gorillas inhabit the montane cloud forest of the Virunga range. Occasionally they go into the afro-alpine meadows (4,000 m) where temperatures are subfreezing at night and there is little suitable food to forage on. |

## Mountain Gorilla. African Wildlife Foundation.

https://www.awf.org/wildlife-conservation/mountain-gorilla

| The page says | The source says |
| :--- | :--- |
| Up to 220 kilograms | Weight 135 to 220 kilograms (300 to 485 pounds) |
| the only great ape whose numbers are growing | Only great ape with increasing population |
| Cloud forests and dense bamboo slopes of the Virunga volcanic mountains and Bwindi Impenetrable Forest | Dense forest, rainforest, bamboo forest, mixed forest, subalpine grassland on the volcanic peaks (note: cloud forest: adw-gorilla-beringei 'montane cloud forest of the Virunga range'; Bwindi is in this source's park list) |
| Wild celery, bamboo, thistles, wood, and roots | They favor celery, thistles, wood, and roots (note: bamboo: elgart-berry-2004 tested bamboo among the gorillas' food plants) |
| is one of two subspecies of the eastern gorilla | This great ape is one of two subspecies of the eastern gorilla |
| A mountain gorilla eats up to 18 kilograms (40 pounds) of vegetation a day | These great apes can eat as much as 18 kg (40 lb) of vegetation each day. |
| Its favorites include celery, thistles, wood, and roots, and it rarely needs to drink, because its juicy food and the morning dew on it are full of water | They favor celery, thistles, wood, and roots, and they rarely need to drink because they consume succulent vegetation which is full of water as well as morning dew |
| Mountain gorillas live in three countries, across just four national parks: Bwindi Impenetrable, Mgahinga Gorilla, Volcanoes, and Virunga | These great apes live in three countries spanning four national parks — Bwindi Impenetrable National Park, Mgahinga Gorilla National Park, Volcanoes National Park, and Virunga National Park. |
| that thick black coat helps insulate them from the cold | Their thick black hair helps insulate them from cold weather. |
| The IUCN moved mountain gorillas from Critically Endangered to Endangered in 2018 | Declared endangered in 2018 by IUCN ... The biggest threats to this once critically endangered great ape's survival |
| About 1,000 live in the wild, according to the most recent census | Only about 1,000 of these great apes remain in the wild, according to the most recent census. |
| they are the only great ape whose population is increasing | Only great ape with increasing population |
| They live in groups of 2 to 40, each led by a silverback | live in groups of two to 40 led by the silverback (note: 2 is the source's 'two') |
| Poachers often target infants | Unfortunately, infants are often targeted by poachers. |
| conflict in the Democratic Republic of Congo threatens the gorillas' future | A future marred by conflict. War in the Democratic Republic of Congo |
| As more people move in close to the gorillas, they bring the risk of human diseases such as flu and pneumonia | As people move closer to these endangered apes, they also bring the risk of human diseases such as the flu, pneumonia, and even Ebola. |
| Up to 18 kilograms (40 pounds) of vegetation a day | These great apes can eat as much as 18 kg (40 lb) of vegetation each day. |
| Their favorites include celery, thistles, wood, and roots, and they rarely need to drink, because their juicy plants and the morning dew on them are full of water | They favor celery, thistles, wood, and roots, and they rarely need to drink because they consume succulent vegetation which is full of water as well as morning dew |
| that thick black hair helps insulate them from the cold | Their thick black hair helps insulate them from cold weather. |