Reference Base The relevance of 'territorial' behaviour in black rhino t... |
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Adcock, K., 1994. The relevance of 'territorial' behaviour in black rhino to their population management: pp. 82-86, fig. 1, table 1
| In: Penzhorn, B.L. et al. Proceedings of a symposium on rhinos as game ranch animals. Onderstepoort, Republic of South Africa, 9-10 September 1994: pp. i-iv, 1-242 |
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Location: |
Africa - Southern Africa - South Africa |
Subject: |
Behaviour - Social Behaviour |
Species: |
Black Rhino |
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Territorial behaviour is indicated by the repulsion of competing conspecifics from an area occupied by one individual, through overt defense or advertisement.
Territorial black and white rhino males show aggression to other rhino which are not tolerated, and chase them away. The clarity of the territorial boundaries is uncertain, but territories are marked by spray urination, foot scraping and defaecation on accumulated dung piles. These probably define a core area within a wider home range where territorial defense is less rigorous, but still not absent in black rhino. Because of this fuzziness, we will refer to rhino 'ranges' in this paper.
'Territorial' behaviour is of relevance to rhino population management, because it sets a limit to the numbers of competing rhino (mainly males) that can co-exist in a given reserve. When these numbers are exceeded, rhino social pressures escalate (mainly among males, but possibly also among females), leading to fighting, injuries and rhino deaths.
(The information here relates to mainly D.b.minor; D.b.bicornis the desert-adapted rhino, show different tolerance behaviours.)
RHINO TOLERANCE AND COMPETITION
Males
Information from Pilanesberg and other areas indicates that at the age of ca 10 years, male black rhino become suitably big, mature and pushy to start establishing a territory for themselves. Up to this stage, they are to a greater or lesser extent tolerated by established bulls, but run a serious risk of being killed or injured by these bulls if they are not suitably subordinate or careful.
The mothers of young bulls (from 1,5 to ca 7 years old) can play an important role in shielding their sons from the aggression of the big bulls. In Pilanesberg, young bulls in areas surrounded by established bull ranges have close ties with their mother until 6-8 years of age. Those in areas which have few established bull ranges around them start to break away from their mother at 2-4 years.
When a young bull does try to establish himself in a territory, he either has to do so in an unoccupied area, or fight another bull to win some turf. In Pilanesberg, such 'upstarts' have little hope of winning a territory off a prime-aged bull (ca 1 7-30 years old), but can drive out or kill older bulls who are on the decline physically. Old bulls, if not killed, will move out to a quiet part of their former range and live a fringe existence (in terms of rhino social life) until they die.
Females
Female rhino are largely tolerated in males' and each other's ranges. A significant number of females are killed by fighting injuries however. Old female black rhino seem to be particularly prone to sustaining injuries to their rear ends. This seems to indicate that they are not being tolerated; but whether this is because of their reluctance to mate with males, or whether other male or female rhino are exhibiting dominance over these grannies, is unknown.
There is some indication that sub-adult females do not have it all their own way either. Firstly, Pilanesberg information shows that female calves break from their mothers at 2-4 years, and tend to spend the next 3-4 years wandering far and wide before settling into a home range and calving.
Secondly, young females are not often killed, but some seem to be pushed to the periphery (socially speaking) and are the butt of some aggression. (One Pilanesberg female died at 10 years without having bred, after lurking around the perimeter of the park as a loner; while another sustained a rump wound and a floppy ear and sticks to another peripheral range).
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