What you need to know about mountain gorillas
Friday, September 07, 2018
Rwanda mountain gorillas from the Susa group, one of the biggest gorilla families in Volcanoes National Park. Sam Ngendahimana.

The rugged beauty of Rwanda’s mountains in the north is part of the Virunga Massif, the habitat for the largest surviving population of the Mountain Gorillas in the world.

The last census of the gorillas, which was conducted in 2016, put the population in the Virunga Massif at 604.

The Volcano National Park (VNP), which is the home of the endangered primates on the Rwandan side, extends over 60 square miles, nearly the size of Kicukiro District and more than a quarter of Musanze District where the park is located.

Since 2005, new born members of the gorilla kingdom are named in a ceremony known as Kwita Izina and at this year’s ceremony, which was marked on Friday, 23 were named in a colourful event that attracted many international, regional and local dignitaries.

Today, VNP is one of the best tourist destinations in East Africa, attracting thousands of visitors every year.

Living without leaving each other

Leonard Mugiraneza, who has followed in the footsteps of his father as a game ranger at the Volcano National Park, says that one of the peculiar things about the gorillas is that, despite their massive size and energy, they’re very peaceful creatures.

Mugiraneza holds a Bachelor’s degree in Game Ranging.

Gorillas can live solo or in families, he says. When in a group, they are very patriarchal; the male gorilla is dominant and the head of the family.

According to Rwandan researcher, wildlife veterinary doctor and field epidemiologist, Dr Jean Felix Kinani, a gorilla position in their society is categorised according to their age of maturity.

For instance, a breast-feeding infant lasts between 3 and 4 years while juvenile varies from 3-5 years. The sub-adult and adult group range from 5 to 9 years and black-backs between 8 and12 years.

By 13, a male begins to gain a silverback –a symbol of total maturity that allows it to make, control and defend family. The life expectancy of a male mountain gorilla is to 45 while that of a female is 50 years.

Male silverbacks weigh between 180-220Kgs and eat over 30 kilogrammes of vegetation a day.

A grown female eats around 15 kilogrammes and a weaned young juvenile of 4-5 years feeds on five to seven kilogrammes every day.

Naturally, unlike other wildlife, gorillas do not need to drink water. They get all the moisture they need from their food and morning dew.

While scientists have argued that gorillas don’t like water in general including rain, Kinani says that in 2013 I saw a gorilla drinking water in the Virunga, a rare phenomenon that has triggered his new research.

Communication

While twenty-five distinct vocalisations are recognised among the Gorilla fraternity, Kinani says, five are the most common form of intra-group communication, especially within dense vegetation.

Grunts and barks are, for instance, frequently heard during travelling and used to trace the whereabouts of individual group members or during social interactions when discipline is required.

Screams and roars signal alarm or warning and are often made by silverbacks. Deep, rumbling belches suggest contentment for both food and situations. They are heard frequently during feeding and resting periods.

Why gorillas live in Rwanda’s volcanoes

Several reasons have been advanced for the survival of gorillas in Rwanda’s volcanoes chain including the fact that Rwandans do not look to primates for food, clothing or hunting trophies.

Moreover, experts have said that the cold climate and the rough topography have also kept the destructive hand of man at bay in this area, making it a safe home for the gorillas.

With mountains rising between 3,474 - 4,507 metres above sea level, temperatures can plunge below 10 degrees, making it a closer competitor of Tanzania’s Kilimanjaro in coldness.

The gorillas’ furs blanket them from the chilling coldness of the mountains. 

Kinani and Mugiraneza recognise that the cold weather makes it easier for the primates to move long distances to look for food in the mountains.

This movement increases interactions among groups and fight among silverbacks become inevitable, the two experts opine.

"Obviously, injuries and group destabilisation come next,” Mugiraneza says.

However, high population density around the park put them at high risk of contracting diseases such as the herpes virus.

Kinani says that "because gorillas are similar to humans in many ways, they easily contract diseases from people.”

In order to deal with this challenge, Kinani says, scientists have applied the One Health Approach Concept (OHAC) for effective disease control.

Here, scientists incorporate environmental and ecosystem factors into disease assessments and interventions.

A century of gorillas

The earliest recorded evidence of the presence of the mountain gorillas in the north of Rwanda was in October 1902 when a German expediter shot two large human-like apes during his expedition to establish the boundaries of German East Africa.

The park’s existence and expansion dates back to 1925 when a small area between Karisimbi, Bisoke and Mikeno mountains was set aside to protect the Mountain Gorillas.

Between 1969 and 1973 about 40 per cent of the park was cleared for cultivation of pyrethrum as the park itself was under the Ministry of Agriculture.

Today, RDB is increasing the surface area of the park and gaining more space for wildlife in general.

editorial@newtimes.co.rw