The condition and age of Thomson's gazelles killed by cheetahs and wild dogs

Abstract

The condition and age of Thomson's gazelles (Gazella thomsoni) killed by two species of predators were compared. The wild dog, a coursing predator, was predicted to take a greater proportion of young, old and sick animals than the cheetah, a stalker. As measured by the marrow fat content of limb bones, wild dogs captured more Thomson's gazelles in poor condition than cheetahs. This appeared to be a consequence of their preference for male gazelles, which were in worse condition than females. Cheetahs did not capture fewer young and old gazelles than wild dogs.

Individual Variability

“…predators selecting for different species, size, age or sex classes; predators selecting physically substandard individuals) and be influenced by various factors such as the presence of competitors, the habitat structure or the season (see e.g. Creel and Creel, 2002;Fitzgibbon and Fanshawe, 1989;Kruger et al, 1999;Mills and Gorman, 1997;Pole et al, 2004;Radloff and du Toit, 2004). Ultimately, prey selection drives hunting success and the ability of predators to acquire and maintain body reserves, making it a key determinant of predators' individual fitness.…”

Toward a predictive theory of risk effects: hypotheses for prey attributes and compensatory mortality

“…Moreover, hunting mode is a trait that is readily ascertained through natural history observation of predators in the field.'' As with grasshoppers preyed upon by spiders, vertebrate prey face different risks from predators with different tactics, and their antipredator responses vary accordingly (e.g., antelope responding to stalkers vs. coursers, or solitary vs. pack hunters; Fitzgibbon and Fanshawe 1989, Scheel 1993, Creel and Creel 2002, Caro 2005, Stankowich and Coss 2006, 2007. Because the strength and type of antipredator responses ultimately determine the importance of risk effects, these studies support the argument that consideration of hunting mode will help to frame theory about the strength of risk (Elgar 1989, Hunter andSkinner 1998), age and sex (Childress andLung 2003, Winnie and, body condition (Ovadia andSchmitz 2002, Heithaus et al 2007), position within the group (Hamilton 1971, Keys and Dugatkin 1990, Hunter and Skinner 1998, Stankowich 2003, habitat type (Lima 1987, Scheel 1993, time of day (Elgar 1989, Scheel 1993, and local environmental conditions (Elgar 1989, Lima andDill 1990).…”

Who ends up in the eagle owl pellets? A new method to assess whether water voles experience different predation risk

“…Most studies have therefore been done on large carnivores preying on large prey (e.g. FitzGibbon and Fanshawe 1989;Husseman et al 2003), trained raptors (e.g. Kenward 1978) or on predators that regurgitate prey items (e.g.…”

“…This is especially true for coursing predators (e.g. FitzGibbon and Fanshawe 1989;Sinclair and Arcese 1995), because of higher detectability and/or lower escaping ability of individuals in worse body condition. A poorer nutritional status might also enhance risk-prone behaviours or simply increase time spent foraging (McNamara and Houston 1987), therefore affecting prey vulnerability indirectly.…”