Feeding habits of capybaras and cattle living in the non-insular area of the Lower Delta region were studied. In addition, samples from coypu were also analyzed. This study was made using a microhistological analysis of faeces. Faeces samples were taken seasonally during 2 years, between 1991 and 1993. The results showed that Poaceae was the main consumed group throughout the year for both capybaras and cattle, with the exception of winter, where cattle consumed a higher proportion of Cyperaceae. For the three herbivores, only a few items constituted the most important contribution to the diets. Five food items (Cynodon dactylon, Panicum grumosum, Luziola peruviana, Zizaniopsis bonariensis and Eleocharis spp.) represented more than 60 % of the diet for both capybara and cattle in every season. A similar foraging pattern was shown by both herbivores during the 2 years. Capybara and cattle diet compositions during the same season were similar, except in summer, when both diets were different. This last fact was also observed when the winter diets of the first two herbivores were compared with that of coypus. With the exception of summer, the seasonal trophic niche breadths were similar between capybaras and cattle. However, their values would be indicating a relatively narrow niche in every season, defining both herbivores as selective species. In contrast, coypus can be defined as more generalistic species although they exhibit a less diverse diet than the others. Total and specific trophic niche overlap values suggest that during the critical season (winter), the foraging habits of capybaras and cattle would diverge, compensating for the low plant availability. In the other seasons, the increase in plant availability would lead to a situation of high overlap in the use of resources.Resume. -Les habitudes alimentaires des cabiais et du betail vivant dans la region non insulaire du bas delta du Parana ont ete etudiees. De plus, des echantillons de ragondins ont egalement ete etudies, egalement par analyse microhistologique des feces. Des echantillons de feces ont etc collectes saisonnierement pendant 2 ans, entre 1991 et 1993. Les resultats ont montre que les Poaceae etaient le principal groupe consomme tout au long de l'annee, ä la fois par les cabiais et le betail, ä exception de Phiver, ou ce dernier consommait une plus grande proportion de Cyperaceae. Chez ces trois mammiferes herbivores, un petit nombre d'items constituaient l'essentiel du regime alimentaire. Cinq items (Cynodon dactylon, Panicum grumosum, Luzioloa peruviana, Zizaniopsis bonariensis et Eleocharis spp.) representaient plus de 60 % du regime du Mammalia, t. 62, n° 1, 1998 : 37-52. Brought to you by | New York University Bobst Library Technical Se Authenticated Download Date | 6/2/15 3:43 AM 38 MAMMALIA cabiai et du betail en toutes Saisons. Un schema d'alimentation similaire a ete trouve pour ces deux herbivores pendant les deux annees, sauf en ete oü la composition du regime etait differente. Cela a egalement ete le cas lors de la comparaiso...
