Morphological aspects of the heart of the northern rockhopper penguin (Eudyptes chrysocome moseleyi): possible implication in diving behavior and ecology?

We compared the heart morphology of the small, deep-diving northern rockhop per penguin to the hearts of small, shallow-diving and large, deep-diving p enguin species. The rockhopper penguin had a heart larger than expected for its body mass, and its heart weight/body weight was significantly greater than in the larger Adelie penguin. We found the rockhopper's right ventricl e weight/heart weight to be significantly greater than this relationship in both the larger chinstrap and Adelie penguins. The relationship of the rig ht to left ventricular weights in the rockhopper heart is not different to that of the large, deepest-diving emperor penguin. A larger heart in the ro ckhopper penguin might be related to its diving behavior and ecology if it contributes to diving efficiency during foraging by increasing lung perfusi on during surface recovery. This would lead to decreased surface time.