Uganda/3 – great apes

Uganda has 20 primate species. Seven are nocturnal and the others are diurnal. The smallest are the nocturnal potto and bush baby. The others are old-world monkeys like the Colobus, Patas, and Vervet. We will get a look at many of these in later posts but let’s start with the largest and most charismatic of the group – no not humans – Great Apes; the Chimpanzee and the Eastern or Mountain Gorilla. In addition the Democratic Republic of the Congo has the Lowland Gorilla and the Bonobo, also Great Apes.

Many tourists visit Rwanda, Uganda, and the Democratic Republic of the Congo (DRC) with the explicit goal of seeing these close relatives of ours. Both of these apes are highly social, staying in family units and hanging out with each other eating leaves and twigs and shoots all day. They are also rather easy to locate in the mountains of western Uganda. Humans, like you and me, have about 98.3% the same genetic makeup of these large primates. The differences appear to be great as we look at each other externally, but the similarities between humans, chimps, and apes are much greater than the differences.

Both chimpanzees and gorillas are forest creatures living in Uganda, Burundi, the DRC and Rwanda, at rather high elevations and in dense forests. The Chimpanzees are in trees more than the gorillas are. The average male/female gorilla weigh about 250/450 pounds and the Chimpanzee weighs about 65/135 pounds. If all goes well they both can live about 50 years. Habitat loss due to human agricultural expansion is the greatest threat to the animals. There is a Lowland Gorilla as well in the eastern part of the DRC and each type of gorilla has two somewhat different populations. The fourth Great Ape of the region, the Bonobo, is only found in the jungle forests of the DRC. Gibbons (often called a Lesser Ape) and Orangutans do not occur in this part of the world.

In Uganda the apes are doing well in the protected forests, although habitat loss, primarily to agriculture, limits their potential for population increase. The same in the DRC and Rwanda though the DRC is vast and mostly still undeveloped. Gorilla and Chimpanzee tourism has been a game changer for these countries and for the local people as well. Nowadays there is a good deal of income based on the American, Asian, and European visitor who pays just under $1000 to get to stay an hour with a habituated gorilla group. Chimpanzee tourism also exists but chimps are less predictable and are often moving about – and significantly less expense to visit. Our group stumbled on both gorillas and chimpanzee as we traveled about the countryside.

As you can imagine there have been many books written and extensive research undertaken on both Chimpanzees and Gorillas. Dian Fosse and Jane Goodall have become common, almost iconic, names in America as they have studied and written about these animals. They, and many others, have dedicated (and even given) their lives to further an understanding of these animals. One last note before jumping in to pictures and stories from our trip – humans, chimps, and gorillas are in separate taxonomic categories. These categories have no other relatives interjected; in other words we are all a bit different but the similarities are pretty much linear – we are each others closest relatives.

Gorilla families consist of a large male; aptly named the silverback, several females and young. In this image the male is on the left sitting and looking unhappy. It was a rainy day and they were all quite content to just sit. The young didn’t play and the group didn’t feed. They pretty much just sat. You can get a sense of the Impenetrable Forest by looking beyond the apes. They are in a clearing and surrounded by all sorts of short and tall vegetation. You don’t just walk through this sort of habitat. Our group approached to within 10 feet or so in some instances and there was never any notable interaction between the human and gorilla groups. They ignored us and we ogled them.
The group of observers walked to where the Gorilla family had settled and both humans and apes sat or stood around looking at each other; though the humans did most of the interspecies looking, This is the big male, the family silverback. In the Impenetrable Forest at Bwindi where we were there are a dozen or more gorilla families that are used to being visited by curious humans. There is an equal number of families deeper in the forest that are not habituated to humans. This is the same relationship used in Rwanda and in the DRC. In the three countries where habituation has been successful there are about 40 habituated gorilla families.
In this image the silver back, showing an older male, is visible. We were brought to where the group had hunkered down for the morning by ranger guides with porters hired to carry gear if you wanted. The guides, both men and women, had been informed by scouts who had gone out very early and located the family. The humans started at about 8:30 am after a briefing. The scouts had gone out at sunrise to locate the Gorillas. Once the people and apes were together the guides were able to “speak” with the apes and assure them that everything was OK. There are about twenty known sounds that the great apes use as language and the guides are familiar with them and mimic certain sounds to keep things on an even keel. The local folks can book on as porters and make some cash money. Even where there are daily gorilla treks there are more potential porters than are needed each day. In our group the porters said they are called only once a month or so to rotate in with a group.
The females are quite a bit smaller than the silverback and there are almost always several females in the group. In todays forests it is nice to see that the females are reproducing and that there are young animals in each family unit. Sadly there isn’t enough forest for this to go on forever, but it is a good thing right now.
The youngsters and females are quite close in most cases and many of the young males stay in the family even as they reach adulthood. They just don’t become dominant and rarely breed. In other cases the younger males head off and live alone or try to create their own family group. As females grow older they stay with the family until they are sexually mature and then move off to join another group. They are not always happy with their first choice and may move around for a while before settling in with a new group. They are usually ten years old (or so) when they are first able to bear young. The youngster will nurse for about two years though they will have been nibbling vegetation for well over a year by then.
Chimpanzees are a bit more mobile than gorillas and being quite a bit lighter in weight they are more fluid in the trees. They are scattered all over the area and, although they are in family units, they are not as property oriented as the gorillas. You can find chimps most anywhere in the forest but you don’t always find them in the same place they were in yesterday.
All of the great apes can walk on all fours as well as bipedaly and they also can move (brachiate) through the trees. Silverback gorillas are too heavy to climb and swing once they mature but gorillas of all sizes are in trees at some point. Usually to make a sleeping nest in the evening. Chimps do much the same thing but spend more time in trees seeking figs and fruits more often than do the gorillas.
These chimpanzees were a group of four that had just crossed a road after (probably) raiding a family crop field. The interaction between chimps and local people is a bit strained and not as comfortable as is the relationship with the more sedentary and forest loving gorillas. Note the large ears on the chimpanzees and then go back and look for ears on the gorillas.

The next post will show the Olive Baboon and its skills, brazenness, and introspection. Gorillas and Chimpanzees may be in groups that occasionally reach twenty members, that would be a small number for a baboon troop.

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