www.elsevier.de/mambio Original investigation Diet, habitat use, and relative abundance of pampas fox (Pseudalopex gymnocercus) in northern Patagonia, Argentina By Vero ´nica B. Garcı ´a and M.J. Kittlein Departamento de Biologı ´a, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata; and Consejo Nacional de Investigaciones Cientı ´ficas y Te ´cnicas (CONICET), Argentina Receipt of Ms. 18.5.2004 Acceptance of Ms. 16.11.2004 Abstract Diet, habitat use and relative abundance of pampas fox Pseudalopex gymnocercus were studied in grassland, sand dune, and scrubland habitats, on the Bahı ´a San Blas and Isla Gama Reserve, Argentina. Scat contents showed a generalist diet, where mammals, insects, and fruits were the main food items. Dietary composition differed among habitats; fruits were mainly consumed in sand dunes; insects, mammals, and fruits predominated in grassland; while insects and mammals were frequent in scrubland habitat. The European hare was the most common vertebrate prey and had the major contribution to the biomass of consumed prey. Pampas fox was the most common carnivore of the reserve and used all available habitats, frequenting more regularly scrubland and sand dune than grassland habitat. r 2005 Deutsche Gesellschaft fu ¨r Sa ¨ugetierkunde. Published by Elsevier Gmbh. All rights reserved. Key words: Pseudalopex gymnocercus, carnivores, food habits, Patagonia Introduction The pampas fox Pseudalopex gymnocercus is a common species along southern South Amer- ica, showing a wide distributional range (Jimenez et al. 1996). This fox ranges through southern Brazil, Paraguay, northern Argen- tina, and Uruguay, and occurs in pampas, hills, deserts, and open forests (Nowak 1997). P. gymnocercus display all day activity (Brooks 1992), although they can be elusive during day hours in habitats where they are pursued (Redford and Eisenberg 1992). Food habits studies on this species are very scant (Ma´rquez and Farin˜ a 2003). Pampas’s foxes are persecuted because they are believed to prey on livestock (Alderton 1998, Nowak 1997). In northern Patagonia, fox poisoning is performed for this reason, even though no ecological studies on this fox were carried out in this region. In this study we aim first to describe food habits of pampas foxes during the summer season, a period when the prey base is most diverse because of the occurrence of fruits in the field, and the manifestation of higher activity levels in many species of arthropods and ectothermic vertebrates. We aim also to ARTICLE IN PRESS 1616-5047/$ - see front matter r 2005 Deutsche Gesellschaft fu ¨ r Sa ¨ugetierkunde. Published by Elsevier Gmbh. All rights reserved. doi:10.1016/j.mambio.2004.11.019 Mamm. biol. 70 (2005) 4  218–226