Parental care behavior in the Guiana dolphin, Sotalia guianensis (Cetacea: Delphinidae), in Ilha Grande Bay, southeastern Brazil

Rodrigo H. O. Tardin,Liliane Lodi,Sheila M. Simão,Mariana A. Espécie

doi:10.1590/s1984-46702013000100002

Abstract

Parental care is any form of parental behavior that increases offspring fitness. To the authors' knowledge, this study is the first to analyze the intensity of parental care in the Guiana dolphin, Sotalia guianensis (van Beneden, 1864). The objectives of this study are as follows: 1) to quantify the degree of parental care in S. guianensis in Ilha Grande Bay, Rio de Janeiro; 2) to investigate the influence of behavioral state and group size on the degree of parental care; and 3) to evaluate the differences between the intensity of parental care provided to calves and juveniles. Our results indicate that the intensity of parental care is high in S. guianensis and that care is more intense in larger groups. It is possible that these differences serve to maximize hydrodynamic gains and to minimize risks. Our results suggest that parental care is more intense during travel. A possible reason for this greater intensity is that the feeding dynamics show a more random pattern than other behavioral states. Moreover, the results indicate that calves receive more intense care than juveniles. These results suggest that parent-offspring conflict is possible in the study population.

Highlights

In mammalian societies, the production and care of the young is a fundamental element because useful models of ecology, social behavior and population dynamics can be developed to incorporate the consequences of parental care (WHITEHEAD & MANN 2000)
The objectives of this study are as follows: 1) to quantify the degree of parental care in S. guianensis in Ilha Grande Bay, Rio de Janeiro; 2) to investigate the influence of behavioral state and group size on the degree of parental care; and 3) to evaluate the differences between the intensity of parental care provided to calves and juveniles
Our results indicate that the intensity of parental care is high in S. guianensis and that care is more intense in larger groups

Summary

Introduction

The production and care of the young is a fundamental element because useful models of ecology, social behavior and population dynamics can be developed to incorporate the consequences of parental care (WHITEHEAD & MANN 2000). Most of these studies concentrate on accessible species known through long-term research These species include the North Atlantic right whale, Eubalaena glacialis (P.S.L Müller, 1776) (HAMILTON & COOPER 2010); the humpback whale, Megaptera novaeangliae (Borowski, 1781) (SZABO & DUFFUS 2008); the IndoPacific bottlenose dolphin, Tursiops aduncus (Ehrenberg, 1833) (MANN & SMUTS 1999); and the killer whale, Orcinus orca (Linnaeus, 1758). The age of females at sexual maturity may be approximately 5-8 years (ROSAS & MONTEIRO-FILHO 2002), and calving intervals may range between two and three years (SANTOS et al 2001)

Objectives

Methods

Results

Conclusion