Diet and habitat use by two sympatric canids in the Pampas of South America

Resumo

The crab-eating fox (Cerdocyon thous) and the Pampas fox (Lycalopex gymnocercus) are two canids with very similar food and habitat requirements, which live in sympatry across parts of their distributions. Here we describe the diet and habitat use of both canids in the Pampas biome. The study took place in southern Brazil from December 2012 to December 2013. Diet and habitat use analyses were based on fecal samples, footprints and direct visualizations. Diet overlap was measured using Pianka’s index, while habitat use was measured using presence records from three different environments; forests, edges and open areas. Both canids feed on invertebrates and vertebrates but have preferences for fruits, especially Syagrus romanzoffiana. Pianka’s index showed a high overlap of their diets throughout the year, with the exception of autumn. Regarding habitat use, C. thous preferred to inhabit forested areas while L. gymnocercus was more active in open areas. Our results showed that fruits were the most consumed food item in the Pampas biome. Our findings suggest that habitat use by these two canids is affected by seasonal variation in fruit abundance, but other factors, such as parental care, should be taken into account when explaining how they behave throughout the year.