Dieta de canídeos brasileiros: uma revisão bibliográfica sobre a raposa-do-campo (Lycalopex vetulus) e o cachorro-do-mato (Cerdocyon thous)

Abstract

The hoary fox (Lycalopex vetulus) and the crab-eating fox (Cerdocyon thous) are two sympatric canids in several regions. Although they exhibit important ecological differences—the hoary fox is an endemic species of the Cerrado, associated with open areas and primarily insectivorous, while the crab-eating fox is a more generalist species with broad geographic distribution and dietary diversity. This study analyzed the literature on the diet of these two species, aiming to describe the state of the art in this research field, the methodologies applied, and to compare the main dietary components between them. Studies conducted in Brazil were considered, regardless of sampling period, as long as they presented the frequency of consumed items and the number of fecal samples analyzed. Studies conducted outside Brazil or based on the same dataset were excluded. Based on the analysis of 16 studies published between 1996 and 2020, most focused on the diet of the crab-eating fox (63%), while only 18.5% addressed the hoary fox exclusively, and 18.5% analyzed both species. Scientific production was carried out by small research teams, with an average gap of 5.7 years between data collection and publication, and was predominantly published in English. Research was conducted in nine Brazilian states, with emphasis on Mato Grosso and Rio Grande do Sul, mainly in the Cerrado and Atlantic Forest biomes. All studies on the hoary fox were carried out exclusively in the Cerrado, whereas studies on the crab-eating fox had a wider distribution. Most fecal sampling occurred in protected areas (69%), with an average sampling period of 25 months and mean study area of 6,431.3 hectares. Each study analyzed, on average, 114.2 fecal samples (ranging from 29 to 289). The hoary fox’s diet proved to be highly specialized, with a predominance of arthropods (100% of the studies), reduced presence of plant material (33%), and no vertebrates as main dietary items. In contrast, the crab-eating fox showed a more generalist diet, composed of arthropods (77%), plant material (62%), and vertebrates (54%), notably birds and small mammals. The number of dietary items identified ranged from 15 to 60 for the hoary fox (average of 34), and from 11 to 70 for the crab-eating fox (average of 28.77), resulting in an overall average of 30.3 items. However, five studies did not specify this data. The lack of standardized data, especially regarding area size and number of samples, limits more robust comparisons. Considering their relevant ecological roles as predators and seed dispersers, understanding the diet of canids is essential to assess their adaptation to impacted environments and to support more effective conservation strategies. Moreover, there is a need to expand research on the hoary fox’s diet, promote studies in under-sampled areas and in biomes other than the Cerrado for the crab-eating fox, and encourage investigations in agroecosystems and areas outside conservation units. This study highlights the importance of future research considering sympatric areas to better understand dietary overlap, niche partitioning, and the ecological dynamics of these species within the Cerrado.