Non-invasive Multidisciplinary Approach to the Study of Reproduction and Calf Development in Bottlenose Dolphin (Tursiops truncatus): The Rimini Delfinario Experience

Abstract

Reproduction is a fundamental biological process that occurs only when all other vital needs are satisfied. In cetaceans reproduction takes place completely in water. From courtship and mating tocalf weaning, every step of the reproductive process occurs under the water’s surface. This complicates data acquisition in wild populations, making captive observations a useful complement to wild studies. By allowing close examination of phenomena, studies in captive environments are able to collect long-term data on known subjects, and sample, in detail, complete behavioural sequences while monitoring physiological or acoustic patterns. Studies of reproduction in bottlenose dolphins (Tursiops truncatus) were initiated at Rimini Delfinario (Italy) in 1995. Four bottlenose dolphin births (in 1995, 1997, 2003 and 2007) have occurred since the start of this research. Due to evidence suggesting that mother and calf associations are closest in the first year of the calf’s life, mothers and calves were studied from birth to the end of the first year. Beginning in 1997, studies encompassed the behaviour and physiology of dolphin mothers during gestation. Here, we report results of interdisciplinary studies of reproductive processes in bottlenose dolphins, including aspects of behaviour, physiology, endocrinology, and acoustics. In an effort to reduce the potential for bias brought about by invasive sampling, we investigated methods of sampling expired air from the dolphin’s blow hole as a means of monitoring steroid hormone levels. In summary, our research combines an interdisciplinary network with specialized professional alliances and offers a potentially crucial approach to the biological aspects of reproduction. At the same time, research findings presented here aim to help bridge the gap existing between captive and wild studies in favor of acommon aim of conservation biology.