Africa is the home of the largest primate in the world – the gorilla, which is classified into two groups. The lowland gorillas habituate the dense and flat forests of western and central Africa while the mountain gorillas are found in the mountainous parts of central Africa. While they are quite similar, there are some differences as well. Lowland gorillas have soft, short hair and the mountain gorillas have longer hair. The mountain gorillas stand 4 to 6 feet tall and weigh from 135 to 220 kg (300 to 485 lbs). The lowland gorillas are of the same height but are lighter. Their weight ranges between 68 to 181 kg or 150-400 lbs.
The Democratic Republic of the Congo, Gabon, the Central African Republic, Cameroon, Angola and Equatorial Guinea are the areas where lowland gorillas live. You can find mountain gorillas in the dense mountains of the Democratic Republic of Congo, Uganda and Rwanda. According to the National Geographic, a group of gorillas may claim a territory of about 41 square kilometres or 16 square miles.
Generally, gorillas are herbivores and usually feast on tree pulp, tree bark, roots, fruits and shoots of vegetation. They are also known to eat insects and small animals. They can consume about 15 kg or 40 lbs of vegetation every single day. The diet of lowland gorillas consists largely of fruits, leaves, stems, seeds and partly by caterpillars and termites. Mountain gorillas on the other hand love stems, shoots and leaves, fruits, flowers and roots. They also eat grubs, ants and snails in small amounts.
Gorillas are not solitary animals and are found in groups, called bands or troops. A band could have about 50 members, although there are instances when a group can only have two. A dominant male, often called a silverback, is the leader of a group.
Like humans, a day in the life of a group of gorillas is broken down into different activities. Feeding time is during morning and evening. Midday is spent grooming each other, playing or napping. They sleep in the evening.
Again, just like humans, gorillas prepare their beds in the evening. Before you start imagining that gorilla beds are close to what you see in advertisements for mattress brands, their beds are called nests. Gorillas build their nests on trees, which younger gorillas prefer. The older members of the troops often find spots on the ground.
It might look random, but gorillas choose where they will build their nest for the night. They consider security, that is why most younger gorillas sleep in nests they build on trees. They also consider the amount of vegetation around them, especially for those who are sleeping on the ground.
Gorillas are also very peculiar and particular, since they build a new nest each night, even if the previous ones they used are just a few feet away. Only infant gorillas are exempt from building their own nest, as they bed down with their mothers.
Gorillas start to build the nest before the evening sets in, because they prefer to be in their nests approximately about one hour after dark. Sometimes, they also prepare simpler nests for their midday nap.
The method in which gorillas build their nests is quite fascinating. After locating a good spot on the ground where there’s a nice clump of vegetation, they will pull the branches of nearby plants and bushes into the centre. They interlace the branches to create several layers, in effect, creating a nice, thick cushion or mattress. The interlacing of branches and leaves is also an effective method to anchor them. They bend or break other branches to form the rim of their nest. Other branches are pulled together to form a makeshift roof.
Nests built on trees must be strong enough to support the gorilla’s weight. The gorilla usually finds a fork in the branches to ensure that it will be a sturdy anchor. The primate will then pull down smaller branches toward the centre, following an interlacing pattern to secure the broken or bent branches, with the leaves providing a soft, warm and thick mattress. A roof of clumped branches is usually constructed as well.
Nest building is not unique to gorillas. Their cousins, the chimpanzees, also build nests. But still, the nest-building dynamics is fascinating to watch, if you’re lucky.
Also see: How Climate Change Affects Gorilla Population?