Fachbereich Veterinärmedizin



    Low aggression levels and unbiased sex ratios in a prey-rich environment:
    no evidence of siblicide in Ngorongoro spotted hyenas (Crocuta crocuta) (2002)

    Zeitschriftenartikel / wissenschaftlicher Beitrag
    Wachter, B.
    Höner, O. P.
    East, M. L.
    Golla, W.
    Hofer, H.
    Behavioral ecology and sociobiology; 52 — S. 348–356
    ISSN: 0340-5443
    Institut für Parasitologie und Tropenveterinärmedizin

    Robert-von-Ostertag-Str. 7-13
    Gebäude 35, 22, 23
    14163 Berlin
    +49 30 838 62310

    Abstract / Zusammenfassung

    Avian models of facultative siblicide predict that rates of sibling aggression and the incidence of siblicide should be lower in prey-rich than prey-poor environments,and that siblicide should only occur when fitness benefits outweigh costs. We tested these predictions by comparing data from spotted hyena (Crocuta crocuta)twin litters in the Ngorongoro Crater, Tanzania, a habitat with a high density of resident prey (176 animals/km2)with similar data from the adjacent Serengeti National
    Park where density of resident prey is low (3.3 animals/km2). As predicted, rates of sibling aggression in Crater twin litters were substantially lower than those among twin siblings in the Serengeti. There was no evidence of siblicide in the Crater, in contrast to the Serengeti, where facultative siblicide occurs frequently. The growth rate of Crater cubs in singleton litters was similar to that of cubs in twin litters, whereas the growth rate of Serengeti singletons was higher than that of cubs in twin
    litters. Thus despotic behavior by dominant Crater cubs was unlikely to provide fitness benefits, while dominant Serengeti cubs that eliminated their sibling benefited from increased growth and enhanced survival. Previous studies have demonstrated biases in the sex-composition of hyena litters due to facultative siblicide. No such biases were apparent in Crater litters. Our results provide strong evidence that levels of sibling aggression in spotted hyenas are adjusted in an adaptive manner, and that siblicide is facultative and resource dependent. Our results
    do not support the idea of pre-natal manipulation of offspring sex by female spotted hyenas in response to changes in resource abundance.