Niche separation in sympatric jackals (Canis mesomelas and Canis adustus)

Abstract

Niche separation (along habitat use, activity and dietary axes) between two sympatric jackal species, Canis adustus and Canis mesomelas, was investigated in north-west Zimbabwe. Diet of the two jackal species was flexible and opportunistic and dietary overlap between the jackal species was high. However, C. mesomelas ate more springhares Pedetes capensis, and C. adustus ate more safari camp refuse. To a large extent, differences in diet reflect availability within home ranges. Although interspecific home ranges overlapped by up to an average of 26%, the two species did not intensively use the same areas, and favoured different habitats. Canis mesomelas defended territories in the grassland habitat, which was also the favoured habitat of springhares, the predominant vertebrate prey species in the area. Canis adustus centred their home ranges on centres of human activity, benefiting from the regular, but low quality, anthropogenic food resources. In this study, C. adustus, with the more generalist dentition, had a broader niche than C. mesomelas (dietary diversity C. adustus=4.14; C. mesomelas=3.45). Within sympatric areas, differing activity times may further operate to decrease competition, allowing these canids to co-exist. The activity times of the two species differed, with C. adustus being almost entirely nocturnal. Canis mesomelas, while mostly nocturnal, was also active during the morning and in the late afternoon. The jackals in this study did not have clear-cut niches and it is probable that the extreme flexibility of canids in both diet and behaviour allows these species to co-exist sympatrically over part of their range.