• This study used models to assess how the type of prey caught by artisanal fishermen influenced the occurrence of Guiana dolphins (Sotalia guianensis ) in the region of the estuarine lagunar comple.x of Cananéia (São Paulo, Brazil). Feeding was the predominant of five recorded activities (i. e., traveling, feeding, socializing, resting, and other), based on time of group sighting (70.3%) and during instantaneous sampling (56.3%). RESUMO: O objetivo do presente estudo foi analisar a morfologia do boto-cinza (Sotalia guianensis) para avaliar a existência de variação geográfica no sudeste do Brasil. They also have a somewhat reduced dorsal fin, which is short and extremely wide, giving it an appearance similar to a boat keel. Several seminal studies have described its diet, yet relationships between the species’ feeding plasticity and climate gradients remain unknown.

El tiempo de observación (243:58h) fue transformado en porcentaje y se calculó el Coeficiente del Uso del Área (UA) en parcelas de 0.25 km2. Studies related to Guiana dolphins diet have been intensified during recent years in Brazil (, Ecologia alimentar dos golfinhos da Amazonia, The distribution and numbers of the commercial or potential squid of the Gulf of Mexico and southeastern Atlantic coast. This should go without saying, but Amazon dolphins are not shapeshifters! A média das áreas de vida principais calculadas pelo método kernel foram extremamente pequenas (média = 1.49km² a 50 % UD e apenas 0.87km² a 25% UD (níveis de utilização de distribuição)). Although no significant differences were found in the AUm for depth, the largest surfaces used were found to be at less than 3 m. Dolphins used areas up to 4 km from shore and to 10 m deep, in and outside the EPAA and from 0.7 to 19.8 km to the urban zone. We analyzed the stomach contents of 40 estuarine dolphins, Sotalia guianensis (van Benédén 1864), beached on the coast of Rio Grande do Norte, Brazil, between February 2000 and February 2007.

These electric fields can be relatively strong and can be a highly valuable source of information for a predator, as underlined by the fact that electroreception has evolved multiple times independently. We observed eight types of coordinated feeding tactics, which differed in frequency and in the mean number of individuals engaged in them, and between both areas. The IRI showed that L. breviceps was the main prey for both adults and the young. 1997); pescada-branca, C. leiarchus (Car-valho1963, Borobia & Barros 1989; baré, Umbrina coronoides (Barros et al. In both Pahara inlet and Wauhta lagoon, sightings were more frequent after 1200 than in the morning. Naturalistics observations were performed from coastal viewpoints located in two distinct areas: a more protected of wind's action (bay) and other unprotected for the winds (Bacoparí's beach). For the most part, these dolphins are active both day and night, sleeping in short stints. Data such as the geographical position and group size was collected at 5-minute intervals using focal-group sampling. These dolphins are unbelievably unique, both in shape and behavior. As interações mais freqüentes e duradoras para a área como um todo ocorreram entre bandos mistos (52,16%), seguidos pelos atobás (Sula leucogaster) (21,77%), trinta-réis (Sternidae) (15,35%), fragatas (Fregata magnificens) (7,41%), biguás (Phalacrocorax brasilianus) (2,96%) e gaivotas (Larus dominicanus) (0,35%), mas o padrão não foi o mesmo nos três setores amostrais. Social and foraging activities oscillated significantly, being less intense at high tide in comparison to other analysed tides. Os padrões de movimentos diários variaram sazonalmente sendo os maiores valores de distância percorrida e taxa de movimento encontrados no inverno e no inverno e outono, respectivamente. El APAA fue usada 59.87% del tiempo, donde se encontró la parcela del máximo uso (UAm=0.598). Our results suggest that brain size has co-evolved with extended life history periods in Odontocetes, as it has in primates and birds, and that a lengthened adult period could have been an important component of encephalization in cetaceans. Their backs are light grey to blueish-grey in color while their undersides are pinkish to light-grey. We also analysed feeding plasticity using a regression tree analysis followed by an ordination analysis. Job number added acc. This study aims to describe and compare forage behavioral patterns of the gray dolphin in different age ranges. Due to the incidental capture and other human impacts the species is considered the most endangered throughout its distribution. Overlap with the diet of the spinner dolphin, S. longirostris, in the same region is less; it may feed deeper, to 400m.

In March through May of 1996–1998, we conducted research in the Cayos Miskito Reserve, Nicaragua, to assess the status, ecology, and distribution of Sotalia fluviatilis, a dolphin known from southern Brazil to Honduras. ... Guiana dolphins have a preference for bottom-dwelling fishes (de Gurjao et al. This work reports for the first time the occurrence of the genus Nasitrema in the marine tucuxi.