Territorial Behaviour in Certain Horned Ungulates, With Special Reference to the Examples of Thomson's and Grant's Gazelles

Abstract

An attempt has been made to distinguish between action area, home range, and territory in the Bovidae. The establishing of subjective boundaries is considered to be the most important criterion of territoriality. The existence of such boundaries becomes evident from certain behavioural symptoms; "defence" or better, localized dominance which may lead to intolerance, is one of them. Not all bovids are territorial. Within the territorial species, there seem to be at least two types: (a) The animals, usually in pairs, may, under favourable conditions, stay in their territories permanently; (b) Only the males are territorial and stay in temporary territories, usually for several weeks or months. This last type is obviously more common in horned ungulates than the first one. Within this second type (b), there are species-specific differences. For example, in Grant's gazelle (Gazella granli) , under certain environmental conditions, this type of territoriality is combined with harem behaviour, but in the co-inhabiting Thomson's gazelle (Gazella Ihomsoni) , the females roam through the territories of the males and stay together with the same buck only for a few hours per day. Even within one and the same species, there can be variations, apparently linked with differences in e~vironmental conditions. This is discussed, using the examples of the Uganda kob (Adenola kob), the wJidebeest (Connochaeles laurinus), and Grant's gazelle. Finally, there can be differences in the territori~ b~haviour of the same individual according to the phases of territoriality (beginning, peak, end) whIch IS shown by the example of 'Thomson's gazelle. I intend to speak about three kinds of subjective space in homed ungulates: the territory, the home range, and the action area (Walther 1967). In this paper, I will discuss the latter two only so far as it is necessary to make a distinction from territories. The action area (Aktionsraum) includes all seasonal territories and/or home ranges as well as the migration routes, which connect them, in short, every place on which an animal sets foot during its individual life. The same may be true for a closed group as long as it exists as such. Apparently some colleagues are concerned that this term "action area" could be confused with "activity range" used by certain authors for "home range"_ I feel, however, that a term covering all the places and routes mentioned above, is needed for the description of the life history of an individual or a group, and for the discussion of traditional space systems in certain species, etc. The term "action area" seems to me adequate for this purpose and sufficiently different from "activity range"_ Moreover, "home range" is a well-known and commonly used term. Thus, I do not see a need for a second, synonymous term ("activity range"). The home range means an area in which an animal, or (more commonly) a group of animals stay long enough to become familiar with this area and to establish a space-time system within it. Of course, a home range has an end, but it does not have boundaries. As a consequence, the home ranges of neighbouring groups may overlap one another in part, and, provided that the inhabiting groups are open societies, individuals which have belonged to a given herd in a given home range for some time are completely free to leave this herd and this home range and to join a neighbOUring herd in a neighbouring home range. A territory is a place in which an animal lives for a short or a long period, with a boundary Zo%gica A/ricana 7 (I): 303-307 (1972) 303