Comparison of Bottlenose Dolphin Behavior in Texas and Florida, with a Critique of Methods for Studying Dolphin Behavior

Notas sobre a distribuição, tamanho de grupo e comportamento do golfinho Tursiops truncatus (Cetacea: Delphinidae) na Ilha de Santa Catarina, sul do Brasil

“…Tursiops truncatus é tido com uma espécie plástica com relação às estratégias de caça e forrageamento (Shane 1990b). O comportamento alimentar de T. truncatus pode ser direcionado a peixes solitários ou que andam em cardumes, e as atividades de caça e captura podem ser executadas por botos solitários ou em grupos, em toda a coluna d'água, com variabilidade intra e inter-populacional nas técnicas…”

Behavior Patterns of Bottlenose Dolphins in San Luis Pass, Texas

“…Survey speed was maintained between 10 and 12 knots (18.52-22.22 km/hr) until a group of dolphins was located, then speed was reduced to match the pace of the group. Groups were defined as all dolphins in apparent association, generally engaged in the same behavior (Shane, 1990;Brager et al, 1994;Karczmarski, 1999), and group composition was recorclecl, including numbers of neonates, calves, and juveniles based on body length and position (as in Irwin and Wiirsig, 2004). Photographs were taken of all members of each group using a Nikon D-1 digital camera, with an 80-400-mm zoom lens.…”

“…Socializing was marked by a variable direction of movement, with individuals in close proximity or touching and frequent surface active behaviors. Finally, milling was indicated by the animals remaining in one area with no physical contact; surface active behavior; or long, deep dives and by slow swimming speeds (definitions followed Shane, 1990;Ballance, 1992;Hanson and Defran, 1993). The behavior category "other" included all behaviors that were not readily identifiable and is likely a combination of all behavior categories.…”

Coordinated feeding behavior of the Guiana dolphin, Sotalia guianensis (Cetacea: Delphinidae), in southeastern Brazil: a comparison between populations

“…According to SHANE (1990), learning has an important role in the behavior of T. truncatus. By watching their mothers and other adults, the calves learn where and how to locate and capture prey.…”

“…The following definitions are used in this study: 1) Group: characterized by individuals within 10 m of each other (SMOLKER et al 1992) and engaged in the same activity or moving in the same direction (SHANE 1990); 2) Feeding bout: a discrete and continuous period of feeding (in seconds), in which some feeding tactics occur (VAUGHN et al 2008); 3) Immature individuals: calves are individuals smaller than 1/2 of the adult length and are a light gray in color; and juveniles are individuals larger than 1/2 and smaller than 2/3 of the adult in length (GEISE et al1999); and 4) Tactics: short-duration behaviors within each feeding bout (ALTMANN 1974). We classified the feeding tactics into eight categories (Table I).…”