Activity not submergence explains diving heart rates of captive loggerhead turtles

Marine turtles spend their life at sea and can rest on the seafloor for hours. As air-breathers, marine turtles' breath-hold capacity is a function of oxygen (O2) stores, O2 consumption during dives, and hypoxia tolerance. However, some physiological adaptations to diving observed in mammals are absent in marine turtles. This study examines cardiovascular responses in loggerhead turtles, which have even fewer adaptations to diving than other...