Estudo preliminar sobre a ecologia de Lontra longicaudis (Olfers) (Carnivora, Mustelidae) no Vale do Taquari, Sul do Brasil

Abstract

O estudo foi realizado em duas áreas no Vale do Taquari, região central do Estado do Rio Grande do Sul, Sul do Brasil. Entre agosto de 2000 e dezembro de 2001 foi realizado um estudo sobre a dieta e o uso de abrigos e marcas odoríferas por Lontra longicaudis (Olfers, 1818). Coletaram-se 275 marcas odoríferas, das quais 261 foram analisadas para determinação da dieta. O uso de marcas odoríferas ocorreu por deposição de fezes, sobretudo sobre locais conspícuos das margens dos rios ou no interior dos abrigos. Os abrigos foram formados principalmente por escavação paralela a margem dos rios. Estes abrigos foram altamente reutilizados. Ocorreu predação sobre três grupos de presas: peixes, mamíferos e insetos. Os peixes formam a base da dieta, e as famílias Loricariidae/Callichthyidae, Cichlidae, Pimelodidae/Auchenipteridae e Erythrinidae foram as mais freqüentes nas análises fecais. A ocorrência destes grupos de peixes na dieta é maior do que sua disponibilidade relativa no ambiente.

Trophic ecology and the use of shelters and latrines by the Neotropical otter (Lontra longicaudis) in the Taquari Valley, Southern Brazil

“…Scent-marking behavior plays an important role for the species, and has been reported by many authors (SPÍNOLA & VAUHGHAN, 1995;SOLDATELI & BLACHER, 1996;PARDINI & TRAJANO, 1999, QUADROS & MONTEIRO-FILHO, 2002KASPER et al, 2004a). The Neotropical otter has the habit of sprainting on rocks and on fallen trunks at the margins of bodies of water where it lives, and such behavior, common to many carnivores, usually plays a key role in territory marking and in communication among individuals (GORMAN & TROWBRIDGE, 1989).…”

“…Studies involving L. longicaudis have referred mainly to its diet (HELDER-JOSÉ & ANDRADE, 1997;PARDINI, 1998;COLARES & WALDEMARIN, 2000;GORI et al, 2003;KASPER et al, 2004a, b), to the use of scent marks and shelters (SPÍNOLA & VAUHGHAN, 1995;SOLDATELI & BLACHER, 1996;PARDINI & TRAJANO, 1999;QUADROS & MONTEIRO-FILHO, 2002;KASPER et al, 2004a), and to the species distribution (CHEHÉBER, 1985;CHEHÉBER et al, 1996;BLACHER, 1987;REYNOSO, 1997;GORI et al, 2003). Such studies are favoured because of the habit of the Neotropical otter of defecating (sprainting) in conspicuous sites of its home range, a behavior observed in many other otter species.…”

“…However, it is probable that the species does not dedicate much time attempting to capture large-sized prey. In fact, it seems to show a preference for prey with benthonic habits or relatively sedentary, such as the fishes of the Loricariidae family and crustaceans (KASPER et al, 2004a). These items have been shown to be of great importance in the diet of L. longicaudis in different habitats (HELDER-JOSÉ & ANDRADE, 1997;PARDINI, 1998;COLARES & WALDEMARIN, 2000;GORI et al, 2003).…”

“…The use of shelters by the Neotropical otter has also been the subject of some studies (PARDINI & TRAJANO, 1999;QUADROS & MONTEIRO-FILHO, 2002;KASPER et al, 2004a). Such shelters are usually located close to water, and are generally composed by (re-entrances) holes and cavities in the steep banks, above water level.…”

Treetop shelter of a neotropical river otter cub (Lontra longicaudis - Carnivora: Mustelidae) in an Amazonian flooded forest

“…Junk & Silva (1997) suggested that, in seasonally flooded forests, breeding takes place year-round, peaking at the low-water season, which agrees with Duplaix (1980) for Surinam, but published first-hand data are scant or null. Likewise, although Larivière (1999) states that the species can use hollow logs or trees, he gives no details or references, and the literature seems to describe only shelters in river margins, in extra-Amazonian sites (e.g., Pardini & Trajano, 1999;Quadros & Monteiro-Filho, 2002;Kasper et al, 2004). We report an otter cub found inside a natural tree cavity in Central Amazonia (Anavilhanas Ecological Station, lower Rio Negro, Amazonas, Brazil).…”