We assessed the level of genetic variability and population structure of the common bottlenose dolphin (Tursiops truncatus) in the tropical and subtropical portions of the southwestern Atlantic Ocean and compared the results with previous morphological findings. We analyzed 109 samples of common bottlenose dolphins that were sequenced for control region mtDNA and genotyped for seven polymorphic microsatellite loci. The results suggested that the species in this region can be separated in two major biological units, northern and southern, with an area of parapatry at southern Brazil. The northern unit seems to occur in a wide range of depths, including

ResumoComportamentos de brincadeira são fáceis de identificar, mas difíceis de definir. Sua ocorrência é mais freqüente em animais jovens, apresentando algumas características comuns: falta de função aparente, utilização de comportamentos específicos da espécie de forma exagerada em intensidade ou número de repetições. Estudamos a brincadeira em uma espécie pouco conhecida, o boto cinza, durante 18 meses, na Praia de Pipa, RN. Definimos seis categorias de brincadeira: com objeto, de forrageio, locomotora, surf, social e de impulsão. Os comportamentos descritos ocorreram quando havia filhotes nos grupos observados. Sugerimos que alguns tipos de brincadeira possibilitam o exercício da musculatura, enquanto que outras também permitem o desenvolvimento de relações sociais. A brincadeira com objetos e de forrageio treinam o animal para a pesca, habilidade complexa que deve dominar antes de se tornar independente. Nossos dados sugerem que, à semelhança dos mamíferos terrestres, nos mamíferos aquáticos a brincadeira tem função adaptativa, preparando o indivíduo para a vida adulta.Palavras-chave: Boto cinza, Brincadeira, Habilidades de forrageio, Animais imaturos. AbstractIdentification and description of play in a scarcely studied species, the tucuxi (Sotalia fluviatilis) in a field site Play behavior are easy to identify but difficult to define. It is more frequently displayed by young animals and present some distinguished characteristics: no apparent function and exaggerated repetition or intensity of species-specific behaviors. We studied play behavior in a scarcely studied species, the tucuxi, during 18 months at Pipa, RN, Brazil . We defined six categories: object, foraging, locomotor, social and impulsion play plus surf. The behaviors described occurred only when immatures were present in the observed groups. We suggest that some kinds of play exercise the muscles while others also allow for the development of social interactions. Object and foraging play are opportunities for training of fishing abilities which the animal must master before becoming independent. Our data suggest that, like terrestrial mammals, in marine mammals paly has an adptive function, preparing the individual for adult life.

ResumoO estudo do comportamento animal é uma área de pesquisa consolidada, que cresceu e se diversificou em vários países e que deu origem a disciplinas e abordagens de investigação, como a Etologia, a Ecologia Comportamental, a Neuroecologia, a Psicologia e a Psicologia evolucionista. No estudo do comportamento animal, o etograma é a base para estudos comportamentais de espécies pouco conhecidas, como também para comparar comportamentos de populações distintas de uma mesma espécie. Tradicionalmente, um etograma descreve de forma detalhada eventos comportamentais realizados por indivíduos de uma espécie. O presente estudo apresenta um etograma dos eventos comportamentais realizados na superfície por uma espécie de golfinho costeiro, boto cinza, na praia de Pipa -RN. Palavras-chave: Etograma; Sotalia guianensis; comportamento de superfície. AbstractResearch in animal behavior is a consolidated area whose development and diversification in several countries have originated some subjects and investigation approaches, such as Ethology, Behavior Ecology, Neuroecology, Psychology and Evolutionist Psychology. In the study of animal behavior, the ethogram is the foundation for studies on behavior patterns of distinct populations of the same species. An ethogram traditionally describes behavioral events performed by individuals of the same species in detail. This study presents an ethogram of behavioral events performed on surface by a costal dolphin known as the gray dolphin (Marine Tucuxi Dolphin), at Pipa Beach, RN.

This study revises and updates information on bottlenose dolphin Tursiops truncatusstrandings and sightings in northeastern Brazil. A total of 72 strandings were recorded from 1992 to 2010, and 51 sightings were recorded from 1988 to 2010 along the states from Ceará to Bahia, including Fernando de Noronha and São Pedro and São Paulo archipelagos, Rocas Atoll and Abrolhos Bank. Most strandings were recorded in the states of Pernambuco, Bahia and Rio Grande do Norte. The number of reports was higher during summer, but no statistically significant difference was found between summer and other seasons. The majority of the stranded animals were adults (70.6%). Stranded calves were not observed. Total body length ranged from 138 to 321cm: 138 to 310cm for males; and 168 to 288cm for females. The average adult body length was 281cm (SD = 0.22). For stranding events where sex was determined (n = 29), a highly statistically significant difference was found between the number of males (n = 21) and females (n = 8). A total of six animals (8.3%) showed evidence of fisheries interactions such as net marks or removal of meat, blubber and eyes. Twenty-two sightings were recorded in the northeastern region, mostly in small islands and Rocas Atoll. This finding shows that the bottlenose dolphin is mainly an oceanic species in the region. More efforts are needed to improve our understanding of the populations and conservation status of bottlenose dolphins in this region.

The coloration pattern of the estuarine dolphin, Sotalia guianensis, does not display variations in its distribution and the colour grey, as its common name suggests, is predominant. On the coast of the state of Rio Grande do Norte a dolphin was sighted with atypical coloration in relation to animals from that region. After observing its morphological characteristics, it was verified that the animal was a white specimen of S. guianensis. Although photographic recordings were made, the reddish coloration of the eye cannot be confirmed, a characteristic that would identify the animal as an albino dolphin. Despite not being very frequent, cases of coloration anomalies such as albinism have been previously recorded in 20 species of cetaceans. However, there have been no cases recorded for the estuarine dolphin.