INTRODUCTION:

Fauna of the "Ethiopian Region"

Nowadays we classify mammals under six main regions, each bounded by natural barriers of mountain, desert or sea.

The great northern region is called the Palearctic, and comprises Europe and northern Asia, and is effectively cut off from Africa, not by the Mediterranean Sea but by the expanse of the Sahara Desert, and from south Asia by the Himalayas. The Americas are divided into two regions; the Nearctic, covering North America, is really a Palearctic sub-region, as it has animals with so much in common with those of the Palearctic that it seems likely that the two areas were one until very recent times. The Oriental region lies south of the Himalayas and as far as 'Wallace's Line' which runs between Borneo and New Guinea. The other side of the line is the Australasian region. South America is called the Neotropical region.

The last great region, the Ethiopian region, includes all of Africa south of the Sahara. The fauna of central and southern Africa resembles that of distant south Asia rather than that of North Africa and Europe, because of Africa's longer link with the southern continent.

The African fauna, the fauna of the "Ethiopian" region, as defined by scientists, is in most instances unrelated to any other for at least the past thirty million years. The climatic changes which followed the creation of the world's great mountain chains led the ruminants of Africa's forests to emerge on to the grasslands, followed naturally by their predators. Out from the gloom of the great forests crept the small ancestors of early horses and zebras - animals who were forced to adapt to life on the plains by running faster and faster to escape their enemies. When these creatures were forest dwellers they had four toes on the front feet and three on the hind. Gradually they came to run on the middle toe and the other toes dwindled. Others, who retained two of their four toes, became the antelope, gazelle and deer. These grazing animals also needed better vision to survive and the eyes gradually grew further up the head. Other modifications followed, so that each species was able to survive in its own particular niche in the ecology. Carnivores retained their toes, developed claws, increased their speed with modifications to the spine and the muscles, which together with their forward-looking eyes, enabled them to survive as hunters. The age-old battle between prey and predator is the story of Africa, the end of which has still to be told.

The Miocene did not see the end of the volcanic upheavals, which had so altered the earth's surface. Eastern Africa underwent a period of dramatic volcanic activity. The earth's crust, forced up by immense pressures from beneath, lifted into a vast dome; great cracks appeared, out of which poured rivers of molten rock. The uplift continued, cracked and dropped down in the centre to form the spectacular Rift Valley system, the dominant feature of the Horn of Africa, and the eastern side of Africa.

The two plateau areas which form the sides of the Rift, in what is now Ethiopia, constitute by far the most extensive highland zones in the whole African continent and provide some of the most spectaculat mountain scenery in Africa.

The Decline of the Mammals

The peak of mammalian evolution, the "golden age of mammals", occurred in the Miocene 25 million years ago, and although the Pliocene and Pleistocene ages still had a rich mammalian fauna, it never again reached such spectacular proportions.

From about one million years ago the world was subjected to four ice ages, imposing on the temperate zones arctic conditions to which the existing flora and fauna had to adapt or perish. The tropical zones underwent corresponding pluvial periods, which created the great eroded gorges and gulleys of eastern Africa's high plateau. Countless thousands of species adapted to the new conditions, and as many disappeared. Those that survived were to face a far greater hazard Man.

With the emergence of Man a million years ago, the slow "natural" decline of mammals was dramatically hastened. Man's highly developed brain has been applied to the invention of all manner of methods of destruction.. shooting, trapping, poisoning, flooding and burning. In destroying the animal which he considers to be an enemy, he has also succeeded in destroying countless others. Only four hundred years ago there were approximately 4,226 living species of mammals. Since then thirty-six have be- come extinct, and at the moment 120 more of them are in some or imminent danger of extinction.

Ethiopia's Endemics

Ethiopia's boundaries encompass the major part of the eastern African highland massif. On the northern and western boundaries lie the lower foothills of the main massif. The Great Rift Valley cuts diagonally across the, country from the Red Sea to Kenya, creating a vast desertic depression on the east and a savanna region which shelters a chain of lakes stretching southwards between the walls of the valley itself. Thus the highlands, since their formation, except for the corridor to the south, have been virtually isolated by very dry areas, and five of the seven endemic animals of Ethiopia appear to have evolved here for that reason. They were presumably forced by various circumstances to adopt the characteristics, which fitted them for high altitude existence and ensured their survival in their particular niches of this tropical highland environment.

The first of these, the Walia Ibex, is the southern- most, of the world's wild goats. A descendant of Palearctic stock, it and the closely related Nubian Ibex, which inhabits Northern Eritrea, Sudan, Yemen, northern Egypt, and Saudi Arabia, are the only members of the goat family found in Africa (other than domestic goats), and are presumed to have arrived here from Iran and Arabia, or up the Nile from Egypt. Their common ancestor likely became established at a lower altitude and the Walia evolved into a separate species by being gradually pushed further into the highlands (probably by the activity of Man and the spread of pastoralism). In making special adaptations to its new environment it became sufficiently distinctive from the Nubian Ibex that it is now considered as a separate species in its own right.

The Gelada baboon, which also inhabits the High Semyen and one or two other montane habitats in Ethiopia, is the only surviving representative of a once widespread group of primates of the genus Theropithecus, one of which was as large as a gorilla. The present population of Geladas probably were able to adapt to, and occupy, a habitat too steep and poor in vegetation for other baboons.

The Mountain Nyala is also an interesting case. Belonging to the familyTrageliphidae - the spiral- horned antelopes, which includes the Nyala which inhabits southern Africa, to which it may be a close relative-it could be an unusual instance of a species migrating up the Rift corridor to adapt in the course of time to a highland existence. Until recently unknown to the world of science, the Mountain Nyala has not been sufficiently studied for definite statements to be made about its origin, but it may well constitute an important faunal link with southern Africa.

The bushbuck family evolved in Africa and consists of many and widespread sub-species, and over forty races, which inhabit a wide variety of habitats. Menelik's bushbuck has adapted to a high altitude existence.

The fifth highland endemic is the Semien fox, an animal which has defied classification through several generations of scientists. Not really a fox, nor a dog, nor a wolf, nor a jackal, the Semien fox is now classified as the only member of its genus, Its origin being unknown.

Ethiopia's other two endemics - the Somali Wild Ass and the Swayne's Hartebeest - are not restricted to the highland massif, being both creatures of the lowlands, and are endemics only by virtue of the massive slaughter of' their once considerable numbers in other regions, and the restriction of their habitat by pressure of domestic stock. The tiny populations, which remain happen to have been cornered within the boundaries of Ethiopia.