Heart rate during overnight rest and while diving were recorded from five emperor penguins with a microprocessor-controlled submersible recorder. Heart rate, cardiac output and stroke volume were also measured in two resting emperor penguins using standard electrocardiography and thermodilution measurements. Swim velocities from eight birds were obtained with the submersible recorder. The resting average of the mean heart rates was 72 beats min-1. Diving heart rates were about 15% lower than resting rates. Cardiac outputs of 1.9-2.9 ml kg-1 s-1 and stroke volumes of 1.6-2.7 ml kg-1 were similar to values recorded from mammals of the same body mass. Swim velocities averaged 3 m s-1. The swim speeds and heart rates suggest that muscle O2 depletion must occur frequently: therefore, many dives require a significant energy contribution from anaerobic glycolysis.
So long Andy and welcome Monica
We say a fond farewell to Andy Biewener who, after 20 years and steering hundreds of manuscripts through peer review, will be stepping down from his role as JEB Editor. We are delighted to welcome Monica Daley to the team in his place.
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