The Caprinae are characteristic ungulates of palaearctic mountain regions. The Walia ibex, Capra ibex walie, a member of the Caprinae, has colonized successfully the Simen mountains in Ethiopia, and as such presents an interesting act in the history of the Caprinae. Apart from the question of how the Walia ibex or its ancestors ever reached the Simen mountains, the only place it occurs, I would like to stress a further point: about half of the existing ungulate species in the world are endemic to Africa. Eightyseven species of the Artiodactyla are reported to live in this continent, while there are only 17 in South America (Haltenorth 1963, Delany and Happold 1979). Such abundance of ungulate forms must have been attended by optimal utilization of the various habitats and form co-adaptation of sympatric species (Lamprey 1963, Bell 1970, Gentry 1970). Despite such intense com­ petition however, the Walia ibex found its natural niche still open. Obviously, its adaptations to living on steep cliffs have favoured its establishment over the already existing ungulate fauna in an afroalpine mountain area. In fact, none of the Cervids has achieved a similar successful colonisation on the African continent, even though they are much older as a group, and have already shown themselves to be well established on the American and Eurasian continents.

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1 Introduction.- A Reader's Guide.- The Simen, a Unique Afroalpine Community.- 2 The Simen Mountains: Geography and Climate of the Study Area.- 3 The Vegetation in the Simen Mountains and Human Utilization of the Area.- 4 The Walia Ibex.- 4.1 The Walia Ibex: Its Taxonomy and Morphological Characteristics; Age Classes and Horn Growth.- 4.2 When in the History of the Climate Could the Ibex, as a Palaearctic Animal, Have Invaded the Range of the Simen Mountains?.- 4.3 The Reproductive Cycle of the Walia Ibex and the General Grouping Pattern.- 5 Two Possible Competitors of the Walia Ibex: the Klipspringer and the Gelada Baboon.- 6 Further Mammals and Birds Living in the Simen Mountains.- Methods, Techniques and Population Estimates.- 7 Methods of Obtaining Data and Field Techniques.- 7.1 Observation and Recording of Animals.- 7.2 Optimal Time of Day for Spotting Animals and Duration of the Observations.- 7.3 The Grid Pattern System Within the Main Study Area.- 7.4 How Comparable and Representative Are Observations Carried Out from the Selected Fixed Observation Points?.- 7.5 Techniques Applied to Investigate Feeding Behaviour of Walia Ibex, Klipspringer and Gelada Baboon.- 8 Methods for the Analysis of Data on Habitat Selection of the Included Species.- 8.1 The Variables Used in the Analysis of Data.- 8.2 The Procedure in Applying the Stepwise Multiple Regression.- 8.3 Assumptions for Regression Analysis.- 8.4 Transformation of the Main Dependent Variable.- 8.5 Relations Between the Environmental Factors.- 8.6 Transformation of the Independent Variables.- 8.7 Inherent Imperfections in the Data Being Able to Diminish the Multiple Correlation Coefficient and a Test to Detect Possible but Overlooked Influential Environmental Factors.- 9 Estimates of Population Size and Changes of the Walia Ibex.- The Niche and Habitat of the Walia Ibex, the Klipspringer and the Gelada Baboon.- 10 The Habitat Selection of the Walia Ibex, the Klipspringer and the Gelada Baboon According to the Frequencies of Their Visits to the Hectare Fields.- 11 The Habitat Selection of the Walia Ibex, the Klipspringer and the Gelada Baboon with Regard to Particular Environmental Factors.- 11.1 The Gradient of the Slope.- 11.2 The Compass Direction of the Slope with Daily and Seasonal Effect.- 11.3 The Altitude and the Vegetation Over the Seasons.- 11.4 The Relief, the Weather and the Activity.- 11.5 Relationship Between the Gradient, the Vegetation and the Group Size in the Walia Ibex, the Klipspringer and the Gelada Baboon.- 11.6 Observation Success at Muchila Afaf-, Kedadit- and Saha-Observation Points.- 11.7 Conclusions, Comparisons with the Alpine Ibex and Considerations on a Possible Tradition.- 12 Separation in the Habitat of the Walia Ibex, the Klipspringer, the Gelada Baboon, the Bushbuck, the Colobus Monkey, the Simen Fox and the Golden Jackal.- 13 The Plot of the Residuals of the Regression Equation - a Test for Detecting Overlooked, but Decisive Independent Variables.- 14 The Theoretical Distribution Pattern of the Walia Ibex and the Klipspringer Within the Study Area.- Summary to Chapters 10 to 14.- The Social System of the Walia Ibex.- 15 Towards the Social System of the Walia Ibex: Approach, Inferences and Predictions.- 15.1 The Approach.- 15.2 Inferred Behaviour of Distinct Ibex Classes.- 15.3 Predictions Deduced from the Inferred Behaviour of the Sex-Age Classes.- 16 The Social System of the Walia Ibex; Evidence for and Tests of the Above Predictions.- 16.1 Habitat Preference of Males and Females of the Walia Ibex; Tests of the Predictions 1 to 3.- 16.2 Size of Home Ranges; Test of Prediction 4.- 16.3 The Dominant Males Only as Occasional Visitors in Female-Young Groups; Test of Prediction 5.- 16.4 The Rank Order and the Fights Between Walias of Different Classes; Test of Prediction 6.- 16.5 The Marching Order Within the Mixed Groups; Test of Prediction 7.- 16.6 Food Selection of the Walia Ibex of Different Classes and of the Klipspringer with Considerations on Prediction 9.- 16.7 Conclusions and Comparisons with the Situation in the Alpine Ibex.- Summary to Chapters 15 and 16.- Conservational Outlook.- 17 The Simen, an Ecosystem in Danger.- References.