Changes in a population of dikdik, Madoqua (Rhynchotragus) kirki (Günther 1880).

Abstract

In 1968/69 a small local population (deme)--11 to 17 animals on 42 ha--of Kirk's Dikdik was studied in the Serengeti area, East Africa. All animals were known individually and all territorial boundaries mapped. The population was revisited in 1972 and all animals and boundaries were recorded anew. 6 animals of 1968 were still present in 1972, 6 had disappeared and 4 were new. 2 territories were still the same, 1 had been divided up between 2 neighbouring ones, 1 had gained 1 ha. In the following summary of the results the generally formulated statements like "Dikdik do" always are short and stand for the specific statements like "the observed Kirk's Dikdik of the Soit ol Modison deme did". 1. Dikdik live in pairs in territories.--2. The young are expelled from the parental territory at the age of 6 to 9 months.--3. They then are able--nearly fully grown, but the horns of the male male only half of their final size--to establish their own pairbond and territory.--4. The female can produce her first young at the age of 15 to 18 months and is reproductive up to at least 6 years.--5. While the reproductive potential is 2/female/year (gestation period 25 weeks), the realized rate of raised animals in 1968/69 was 1/female/year.--6. Average population age lies around 5 years.--7. Maximum physiological age is 10 or more years.--8. The pair bond is independent of the territorial bond and lasts for life.--9. The territorial bond is independent of the pairbond but does not last for life.--10. Strategical lines of the territorial boundaries are marked by dung areas. The families of both territories each use their own places on these areas. The whole family urinates and defaecates together (one after the other) in a ritualized way.--11. The territorial boundaries can shift. The number of dungplaces along a disputed and/or shifting boundary is higher than along an undisputed stable one.--12. Only the male defends the territory and chases off the grown up male young.--13. The female who does not defend the territory is nevertheless bound to it directly, not only by her bond to the male.--14. The most important open question with respect to the social organization is: How is the grown up female young induced to leave the territory? Can there be circumstances when she can stay?