Physiological Parameters Monitored on Bottlenose Dolphin Neonates (Tursiops truncatus, Montagu 1821) over the First 30 Days of Life.

Bottlenose dolphins (Tursiops truncatus) have been bred under human care for more than 60 years. Calves up to 30 days of life have presented the highest mortality rate, although comparable data for free-ranging neonates within this age group is not available. Husbandry measures to increase survivability have therefore been constantly improved. This work shows the results of a structured veterinary program that established the procedures to collect relevant physiological parameters on 13 calves during their first 30 days of life. Standardized observation protocols facilitated statistical analysis of the respiratory pattern, nursing, morphometric measurements and bloodwork. These allow early detection of health issues. Healthy neonates had longer apnea duration, despite the shape and size of the facility. The nursing pattern showed that successful calves started nursing 3 to 18 h postpartum. Although with different individual patterns, a steady increase in suckling time occurs during the first 24 h of life. The healthy neonates grew 0.428 ± 0.102 kg per day and the complete blood count profile, glucose, iron, blood urea nitrogen (BUN), total protein, Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), Gamma-glutamyl transferase (GGT), creatinine and electrolytes values considered normal for healthy calves are provided. Furthermore, cholesterol, triglycerides, α-amylase, lipase, magnesium and cortisol are reported for the first time for such young calves. A list of indications for prompt intervention is included.

The bottlenose dolphin (Tursiops truncatus) faecal microbiota.

Cetaceans have evolved from herbivorous terrestrial artiodactyls closely related to ruminants and hippopotamuses. Delphinidae, a family included in this order, represent an extreme and successful re-adaptation of mammalian physiology to the marine habitat and piscivorous diet. The anatomical aspects of Delphinidae success are well understood, whereas some physiological aspects of their environmental fitness are less defined, such as the gut microbiota composition and its adaptation to their dietary niche. Here, we explored the faecal microbiota structure of nine adult bottlenose dolphins (Tursiops truncatus) and one breast-fed calf living in a controlled environment. According to our findings, dolphins possess a unique microbiota profile within the Mammalia class, highly resembling that of carnivorous marine fishes. The breast-fed calf showed a distinctive compositional structure of the gut microbial ecosystem, which partially overlaps with the mother's milk microbiota. Taken together, our data indicate that in dolphins the adaptation to the marine niche and piscivorous diet involved the convergence of their gut microbiota structure with that of marine fishes, overcoming the gut microbiota phylogenetic inertia previously described in terrestrial mammalians.

Evidence suggests vocal production learning in a cross-fostered Risso's dolphin (Grampus griseus).

Vocal learning is a rare skill in mammals, and we have limited information about the contexts in which they use it. Previous studies suggested that cetaceans in general are skilled at imitating sounds, but only few species have been studied to date. To expand this investigation to another species and to investigate the possible influence of the social environment on vocal learning, we studied the whistle repertoire of a female Risso's dolphin (Grampus griseus) that was stranded at an early age and was subsequently raised in a group of bottlenose dolphins (Tursiops truncatus). We show that this cross-fostered animal produced vocal signals more akin to those of its Tursiops poolmates than those of Risso's dolphins in the wild. This is one of very few systematic cross-fostering studies in cetaceans and the first to suggest vocal production learning in the Risso's dolphin. Our findings also suggest that social experience is a major factor in the development of the vocal repertoire in this species.