Chimpanzees have already disappeared from 4 African countries, and are nearing extinction in many others.
|Habituated Wild Chimps in Kibale National Park, Uganda|
The estimated population of chimpanzees remaining on earth (for the eastern chimpanzees) is still only approximate because large areas of their range have never never been surveyed. The most recent estimate (Kormos et al. 2003) is 76,400- 119,600 eastern chimpanzees of an estimated 172,700-299,700 total for all subspecies.
The eastern chimpanzee, Pan troglodytes schweinfurthii, is classified as Endangered on the IUCN’s Red List of Threatened Species. These animals live in the Central African Republic, the Democratic Republic of Congo, Sudan, Uganda, Rwanda, Burundi, Tanzania and Zambia. Due to high levels of exploitation, death and injury, as well as loss of habitat and habitat quality as a result of expanding human activities, this subspecies is estimated to have experienced a significant population reduction in the past 20 to 30 years, according to the IUCN Red List. The Red List states, “The causes of the reduction, although largely understood, have certainly not ceased and are not easily reversible,” and states also, “It is suspected that this reduction will continue for the next 30 to 40 years.”
Estimates of eastern chimpanzee numbers by country from surveys within the past 10 years. ‘Known sites’ don’t cover the full range where this subspecies is likely to occur.
Chimpanzees are most often found in moist and dry forests, and forest galleries extending into savanna woodlands. They are omnivorous, and their diet is variable according to individual populations and seasons. Fruit makes up about half their diet, but leaves, bark, and stems are also important. Mammals comprise a small but significant component of the diet of many chimpanzee populations.
Chimpanzees form social communities of five to 150 animals, and there is great cultural variation between chimpanzee populations. Some fish for termites with sticks while others do not; some crack nuts, large snails or even tortoises and eat them, while others do not. Chimpanzees at neighboring sites tend to have similar behaviors.
|A wild Chimp yelling in Nyungwe
National Park, Rwanda
The major threats to the Eastern Chimpanzees including hunting for bushmeat, hunting for trade if infants, habitat loss or fragmentation, and disease transmission. Populations are being hunted across their range, particularly in the DRC and CAR (Central Africa Republic), where they are targeted as bushmeat (chimpanzees are relatively large and provide a reasonable amount of meat compared with other primates). When mothers with infants are killed, the infants are often kept alive as pets and often traded. This illegal traffic in wildlife, from DRC through East Africa, remains high, despite efforts to control it.
While the Congo Basin forest block remains fairly intact, it is gradually being sub-divided by roads and human settlements, which is leading to increasing fragmentation of chimpanzee populations. Roads constructed either to link settlements or for removal of timber from logging concessions allow hunters to enter forests that were previously difficult to reach or inaccessible, which has increased the pressures on chimpanzees.
In East Africa (including Rwanda and Burundi) there’s less killing for bushmeat (although it does occur), but chimpanzee population are declining due to habitat loss and major fragmentations, as forest and woodland is converted to agriculture. Outside protected areas, habitat is fast being lost.
|A wild chimp in Kyambura Gorge|
There is a great risk of disease transmission in East Africa as many chimpanzee populations live in close proximity to people and regularly come into contact with human feaces and other waste. Studies in Kibale National Park show that human gut fauna are found in chimpanzees and other primates that live adjacent to human settlement and that the similarities between the gut fauna of people and primates increases with increasing forest fragmentation. Disease risk is also exacerbated by tourism as people come within a few meters of the animals, enabling transmission of respiratory diseases. In addition, international tourists are more likely to be carrying novel diseases that the chimpanzees have never been exposed to.
The conservation of wild populations is important not only for conservation, but also for the survival of chimpanzee cultures in the region that are invaluable to helping us define our own place within the natural realm.