nonhuman primate relatives are valuable to us in many ways, and the rapid growth of the science of primatology over the past 25 years has reflected this. Studies of these animals have taught us a great deal about the intricacies of our own behavior, they have clarified questions about our evolution and our origins, and they have played a significant role in biomedical research. Furthermore, the importance of primates as key elements of the tropical forest (e.g., seed dispersers) is only starting to be understood.
Unfortunately, wild populations of most nonhuman primates are decreasing all over the world. Many spectacular species like the mountain gorilla (Gorilla gorilla beringei) from Rwanda, Uganda, and Zaire, the golden lion tamarin (Leontopithecus rosalia) and the muriqui (Brachyteles arachnoides) from Brazil, and the indri (Indri indri) and the aye-aye (Daubentonia madagascariensis) from Madagascar are already endangered, and many others are headed in the same direction.
Without a doubt, the major cause of the decline of primate populations is destruction of their tropical forest habitat, which is occurring at a rate of some 10 to 20 million hectares per year (OTA, 1984), the latter figure being equivalent to a loss of an area the size of California every 2 years.
Another very important factor in the decline of these populations is hunting of primates, mainly as a source of food, but these animals are also hunted for their supposed medicinal value, for the ornamental value of their skins and other body parts, and for their use as bait for other animals, or to eliminate them from agricultural areas where they have become crop raiders. The effects of hunting vary greatly from region to region and from species to species, but hunting of primates as food is known to be a very serious threat in at least three parts of the world—the Amazonian region of South America, West Africa, and Central Africa. Many thousands of primates are killed every year in these regions for culinary purposes, and such overhunting has already resulted in the elimination of certain species from large areas of otherwise suitable forest habitat (e.g., the elimination of woolly monkeys and spider monkeys in Amazonia) (Mittermeier, 1987; Mittermeier et al., 1986).
Live trapping of primates, either for export or for local use, plays an important role as well. Live primates are used in biomedical research and testing, or they may be sold as pets or exhibits, both internationally and within their countries of origin. For the most part, this is a less important factor than habitat destruction or hunting, but for certain endangered and vulnerable species that happen to be in heavy demand, it can be quite serious. Species that have been hurt by the trade in live primates include the chimpanzee and the cotton-top tamarin (Saguinus oedipus), both of which were important biomedical research models, and the woolly monkeys (Lagothrix spp.), which were and still are very popular as pets for local people in Amazonia.
All these factors have combined to bring about a worldwide decline in primate populations. According to the International Union for Conservation of Nature (IUCN), one out of every three of the world’s 200 primate species is already in some danger and one in seven is highly endangered and could be extinct by the turn of the century or even sooner if something isn’t done quickly. These are minimum estimates. Very often when specialists go into the field to investigate