Conditioned Variation in Heart Rate During Static Breath-Holds in the Bottlenose Dolphin (Tursiops truncatus)

Previous reports suggested the existence of direct somatic motor control over heart rate ( f H ) responses during diving in some marine mammals, as the result of a cognitive and/or learning process rather than being a reflexive response. This would be beneficial for O 2 storage management, but would also allow ventilation-perfusion matching for selective gas exchange, where O 2 and CO 2 can be exchanged with minimal exchange of N 2 . Such a...