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Gorilla Facts

Relationship Between Gorillas & Humans

From the beginning, the human were part of the Hominidae taxonomy family while the Apes were listed under the Pongidae taxonomic family.

The distinction between these two resulted from the anatomy specialization, differing locomotion and the highly developed human brain.

But overtime, this has been discarded and with the ranking of Chimpanzees close to humans followed by gorillas and Orangutans respectively.

The scientific studies show that the composition in the genes of these apes matches that of humans to a greater extent with a minor variation in the DNA.

The gorillas differ from humans by 1.6% while the chimpanzee differs by 1.2% from humans.

The mitochondrial of DNA which is noted to vary easily, the geneticists were able to identify a variance of 8.8% among humans and chimps while humans and gorillas differ by 10.3%.

However, despite the bonobo and chimpanzee closeness to humans, it can be noted that gorillas resemble humans in many things including the hands and feet and their feet is well set for walking like that of humans as they spend much of their time on ground compared to other apes.

Mountain Gorilla Behavior  

Mountain gorillas are notable social animals which live in cohesive and stable groups held together by extensive bonds between the male and female gorillas.

The relationship among the female gorillas is comparatively weak. Mountain gorillas are known to be non territorial and the lead male gorilla also known as the Silverback aims at protecting the family and not the territory.

The 61% of the gorilla groups have one dominant male and a multitude of females while the 36% possesses more than one adult male gorilla.

The other gorillas opt to exist alone or create exclusive male groups with one dominant male and then many young male gorillas.

The mountain gorilla families feature an average size of ten (10) individuals though the range is between 5 to 30 individuals.

A stable mountain gorilla group has one dominant Silverback with unquestionable leadership along with a subordinate male which is normally a half brother, adult son or a younger brother of the dominant Silverback.

After these two, there is always one or two black backs which perform the watchman role, three or four sexually mature females with close bond with the dominant Silverback, about 3 – 6 Juveniles and the range of infants.

The male mountain gorillas and approximately 60% of the females tend to leave their mother groups at the age of 11 years and the separation process can last sometime with them starting to forage on the group age up-to when they eventually disappear for good.

These departed male individuals tend to leave alone or with in an exclusive male group for about two to five years from where they attract females to join them and form a new gorilla family.

The female gorillas depart the natal groups at around the age of eight and can join another family direct or constitute a new one with a lone male gorilla.

The main Silverback determines the movements of the entire group including the feeding areas throughout the year.

The Silverback also solves group conflicts and protects the groups against external threats a reason why it is always willing to fight to the last breath in case of an attack from a wild gorilla, leopards or humans.

It is also the focus centre in the periods of resting and the young gorillas prefer to stay close to him and engaging him in their playful games.

In the event where the mother gorilla dies, the Silverback can take care of the baby including sharing of the nest.

The experienced Silverbacks can even remove the snares set by poachers from the hand or feet of the respective family member.

In the event where the Silverback loses his life to either natural death or accident and there is no capable successor, the group faces disruption and can separate or a foreign male can take them.

The new Silverback at times kill all the infants left behind by the former Silverback to allow the females conceive his though this is not common among the stable gorilla families.


The Mountain gorillas are noted to be shy and gentle despite of their strength and power which limits the internal group aggression.

But in the event, where the two gorilla groups meet, fighting is likely to occur between the two Silverbacks using their sharp canines at times resulting into deep injuries. The aggression process takes the following steps;

  1. Progressive quick hooting
  2. Symbolic feeding
  3. Bipedal rising
  4. Vegetation throwing
  5. Chest beating using cupped hands
  6. One leg kick
  7. Running sideways
  8. Vegetation slapping and tearing
  9. Ground thumping with palms ending the display


The relations in the Mountain gorilla groups are normally established and reinforced during the midday resting period.

This includes mutual grooming that reinforces social bonds and cleaning the fur from dust and parasites though it not to a larger extent compared to other primate species.

The young gorillas play always and climb trees more often than adult gorillas.  The games include; chasing, wrestling and somersaults.

Other members including Silverbacks do tolerate the activities and at times participate in them.


The Mountain gorillas feature 25 vocalizations which are used for communication in different situations. The grunts and barks are used by the gorillas while on the move and assist in keeping the members together.

These very sounds can as well be used while calling for discipline during social interaction. The roaring or screaming are used as warning or alarm sound by the Silverback. The rumbling belches are made in times of resting and contentment.


Mountain gorillas are noted to fear reptiles for reasons known to them.  Though the infant gorillas can chase whatever comes of their way in motion, they desist from doing so to Reptiles and caterpillars.

The Mountain gorillas are also recorded to be water fearing and would attempt to cross streams on walking on logs and in the event where such options do not exist, they cross bi-pedally.

They also dislike rain and can stand under the trees and caves in case of heavy down pour.

Gorillas and Climbing

The Mountain gorillas largely are land dwelling species with 5 – 20% of their day time spent in trees. This is comparatively little time compared to Chimpanzees and Orangutans.

The Gorillas often climb to secure fruit or as part of playing especially for the young ones.  They climb quadrupedally and on minor occasions can jump from a branch to branch.

The Silverback gorilla because of their size can hardly get off the ground to climb a tree but can as well climb a tree branch if it can hold their weight.

Day Time of Mountain Gorillas  

The Mountain gorillas are up for foraging early in the morning around 6am, settle for a midmorning rest and then spend the afternoon foraging before settling for overnight.

However in cases of coldness and forecast, the gorillas can delay in the nests beyond 6am.

The half day of the Mountain gorilla time is spent on foraging and the 1/3 is the resting time.  The 6.5% of the mountain gorilla time is spent moving from one point to the other while the 3.6% is spent while engaging in social behavior.

The social interaction occurs during the resting period which is around Midday making it an important period in the social life of mountain gorillas.

Gorillas and Water

The Gorillas like the other apes and humans are not swimmers naturally and would wish to avoid big water bodies.

The adult and the young gorillas are known to play with water and during their movements; they can walk bi-pedally through swamps with the water reaching their waist.

In the event where the rain shower is too heavy, the Mountain gorillas stand in one position waiting for it to end.

They can sit under the available shelter like a cave or a tree.  However, unlike the Bonobos and the Orangutans, gorillas do not use leaves to cover themselves.

Mountain Gorilla Evolution, Taxonomy and Classification

The Mountain Gorillas are recognized to have originated from the Old World Monkey and Apes noted to have lived in the parts of Arabia and Africa at the commencement of the Oligocene epoch approximately (34-24 million years ago).

The fossil evidence shows the thriving of hominoid primates (apes) in East Africa about 18–22 million years past.

But unfortunately, the fossil record about the mountain gorillas in the area thrive is not clear thus limiting their in-depth understanding of their evolutionary history.

At a range of 9 million years ago, the group of primates which later evolved into gorillas split from the common ancestor of Chimpanzees and humans leading to the formation of gorilla genus.

Though this earliest relative is not clearly known, it is noted that Proconsul Africanus might be the one.

The Mountain gorillas area are known to have separated from the eastern lowland gorillas over 400,000 years ago and the two are noted to have separated from the western lowland gorillas around 2 million years past.

Regarding the classification of Mountain gorillas, there has been a debate over this issue which has marked the entire classification up to their current naming.

In the year 1947, the gorillas were named Troglodytes but in 1952 the name gorilla was brought back.  Collin Gloves proposed in 1967 that gorillas be categorized under ones Species and named Gorilla gorilla and then 3 sub species namely; the western lowland gorilla (Gorilla gorilla gorilla), the eastern lowland gorillas (Gorilla gorilla graueri) and then mountain gorillas (Gorilla gorilla beringei) normally explored on gorilla trekking safaris and tours in Uganda and Rwanda.

This ran until 2003 when the IUCN classified the gorillas into two species namely; Gorilla gorilla and the Gorilla berengei.

Gorillas and Sleeping    

The Mountain gorillas sleep in nests which are built on ground and also in trees putting in consideration of the security and the available vegetation.

The Mountain gorillas put up new nests every evening as they cannot use their previous night’s nests. Apart from the infants that share with their mothers, all other gorillas put up individual nests which they enter into at half an hour to the dark. The mountain gorillas rarely construct nests for Midday rest.

For the ground nest, the mountain gorillas pull plant branches to the middle and anchor them to one another to form a bed and then other plant branches are bent to create the nest rim.

For the tree nests, the branch forks or similar structures are inter-joined to create a nest whose strength would be according to the size of the mountain gorilla weight.

The young and female gorillas tend to sleep in trees which is not the case for Silverbacks due to their gigantic weight.

Mountain Gorilla Conservation

Population size and growth rates

Mountain gorillas are critically endangered species as recognized by the International Union for the Conservation of Nature and the habitat in which they live is also conserved fragile and the combination of these makes their conservation rather complex.

However, with the rigorous efforts of the respective national governments to conserve this precious species, their numbers have been on the rise despite the sad past.

The studies indicate that the mountain gorilla population now stands at 880 individuals both in Bwindi Impenetrable National Park and in the Virunga Massif where the Uganda’s Mgahinga Gorilla National Park, Congo’s Virunga National Park and Rwanda’s Volcanoes National Park are found.

The are other 3 young mountain gorillas at Congo’s Senkwekwe Orphanage Center that were affected by trauma due to snare injuries, poaching and loss of the mother.

The Official website of Virunga National Park publicized an increment of Mountain gorilla population in the Virunga block by 26.3% in the month of December 2010 in the range of seven years indicating that that there was an average increase of 3.7% per annum.

The 2010 gorilla census which was conducted in the Virunga massif put the figure at 480 mountain gorillas rising from the 2003 figure of 380 mountain gorillas, 1989 figure of 320 members and the 1981 figure of 254 gorillas.

The 2011 study in Bwindi Impenetrable National Park indicated the presence of 400 mountain gorillas rising from the 2006 figure of 340 mountain gorillas and the 1997 figure of 320 mountain gorillas.

However the methods used were rather traditional like dung collection but the genetic analysis test put the mountain gorilla figure at 300 in Bwindi Impenetrable by the year 2006.

The Habituation of Mountain gorillas is noted to have brought a positive wave in the world of Mountain gorilla conservation as the habituated gorilla groups registered high potential for population increase than in the opposite group.

The activity gives the gorillas an opportunity to interact closely with humans and as a result they can be helped in case of any problem including diseases and snares.

However, to keep the ecosystem balancing, there is a considerable section of the Mountain gorillas that are not habituated which would save the fate of gorilla extinction in case a very dangerous human pathogen is carried to the habituated gorillas.

Mountain Gorilla Physical Description

Mountain gorilla feature long and thick fur than other gorilla species something that enables them to thrive in the cold mountainous areas where they thrive.

These Species are distinguished by nose prints which are different from one another. The male mountain gorillas tend to have an average weight of 195 kg stretching to 150cm in height on an upright stand and can on certain occasions double the size of the female gorillas. The female Mountain gorillas feature an average size of 100kg and rise to 130cm in height.

Mountain gorillas are notably the second in size after the Eastern low land gorillas in the primate world. The mature male gorillas possess bony crests on top and at the back of their skulls which gives their heads a conical shape.

The crests hold the strong temporalis muscles which are attached to the lower jaw. However, these crests are not very prominent in female gorillas.  The Mountain gorilla eyes are dark brown with a black ring surrounding the Iris.

The adult male gorillas derive the name Silverback from their Silver patch that grows in their back during their mature age.

The fur on the arms is considerably longer than the hair on the back of the Mountain gorillas.

Mountain gorillas are noted to be terrestrial species and quadrupedal i.e. able to walk with four legs though they have the capacity to run bipedally for a distance of 6m.

This Species can climb trees to extract fruit but this is on condition of the tree branch capacity to hold their weight. The gorilla arms are comparatively longer than their legs and they apply knuckle walking.

The Mountain gorillas are diurnal in nature with their activities running from 6am to 6pm. This time is utilized for foraging and resting around midday.

Threats to Gorillas

Mountain gorillas are recorded as critically endangered on the IUCN red list majorly due to their low birth rate and fragile habitats and unstable surrounding political environment.

The threats of Mountain gorillas in Virunga Volcanoes include the disturbance by loggers, grass and honey collectors, cattle herders, smugglers and poachers.

The poachers at times set the wire snares targeting other animals like forest antelopes including duikers but gorillas end up becoming victims resulting into the loss of their feet or hand or death altogether.

The Western lowland and Grauer’s gorilla are sadly hunted by the locals for meat. The gorillas also encroach on people’s gardens causing substantive destruction and the local react by killing some.

The habitat loss is also on the rise especially due to increasing population pressure among the communities that surround these gorilla habitats.

People are always in search of more land for agriculture leading to encroachment on the gorilla habitats.

The Ebola virus is also another dangerous threat especially to the western lowland gorillas.

What do Gorillas Eat?

The Gorilla feeds on what is available at a given time of the year and in a given habitat. To a larger extent, the Mountain gorillas consume plenty of green plant parts while the lowland gorillas consume much fruit.

During the dry season, there is a limit on the juicy fruits availability making the gorillas to opt for tree barks and fruits as well.

But in general, the Mountain gorillas are fond of vegetarian diet where they consume bamboo shoots and stems along with some fruit whereas the western lowland proceed to eat ants and termites and tend to break the nests of termites to eat Larvae.

It can be noted that since the fruits grow on trees, the gorillas at various age levels climb trees to extract them though the capacity of the tree to handle the weight would determine which gorilla to climb.

The Western lowland gorillas are notable to have high fruit consumption levels compared to their eastern counter parts but still do not go beyond the Chimpanzees and Orangutans.

Mountain gorillas are fond of eating nettles, thistles, celery and Galium while the western lowland gorillas are fond of feeding on plant species belonging to ginger and arrowroot families.

The adult Grauer’s gorilla male can feed up to 30 kg of plants per day whereas the female gorillas take about 18kg.

The gorillas are known to posses strong chewing muscles allowing them to breakdown all the plant materials gathered.

The gorilla teeth resemble those of humans except their long canines existing in adult male gorillas and used for fighting not feeding.

Mountain Gorillas and Illnesses

The Mountain Gorillas are susceptible to human diseases a reason why control measures like the 7m rule are put in place to reduce the transmission risk.

Apart from the human diseases, the habitats of Mountain gorillas live in cold environment leading to the development of respiratory related diseases like Pneumonia which at times results into loss of life.

The Mountain Gorillas rarely suffer from teeth cavities due to less fruit consumption thus little sugar. But the bad tartar in Mountain gorillas results into periodontitis leading to the dissolution of the jaw bone resulting into the teeth loss.

Most of the Mountain gorillas have intestinal worms which are at times similar to those of humans but with some specifics limited to gorillas.

The Malaria parasites which are rather different from those that cause human sickness also affect Mountain gorillas.

The wire snares normally set by poachers with intention of catching other fauna like duikers often catch the gorillas leaving them with severe injuries and at times can lead to death.

Dangerous diseases like Ebola can be transmitted from humans to Mountain gorillas thus remains a big threat as well.

The Habitat of Gorillas

Mountain gorillas are noted to thrive in the verdant tropical forests of Sub Saharan Africa limited in scope to Bwindi and Virunga highlands at a 900km distance from their western low land counter parts.

This habitat used to be a joined one before the occurrence of the last ice age that resulted into the formation of forest patches and dry lands at the center of it.

The dry land led to the establishment of savannah vegetation that would not accommodate the gorillas leading to their movements in different direction in search of adequate food supply areas.

Though the area later returned to the equatorial vegetation type, it was already late for the mountain gorillas to re-unite.

This separation formed a background for the present day difference observed in these gorilla Species.

Apparently, the western gorillas are known to live in Nigeria, Cameroon, Central African Republic, Republic of Congo, Gabon, Angola, Equatorial Guinea, and extreme west of Democratic Republic of Congo.

The Eastern gorillas including the Mountain and low land gorillas stretch over coverage of 112,000km2 in the countries of Uganda, Rwanda and the Democratic Republic of Congo but the Mountain gorillas only live in the Mountainous landscapes of Bwindi Impenetrable National Park, Mgahinga Gorilla National Park, Virunga National Park and Volcanoes National Park

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