Jenifer Hurley explains that for most organisms metabolism is a continuum that starts with sleep and peaks at extreme exertion. But 60 years ago, P. F. Scholander measured the metabolism of mammals that he forced to dive, and found that their diving metabolic rate was even lower than when they were resting. Metabolic heresy! However, Hurley and her colleague Dan Costa might have laid this question to rest with diving data from California sea lions.
People had tried to reproduce Scholander’s results using free diving animals, but with no success until Hurley tackled the problem with the help of four adult sea lions: Beaver, Hoover, Sake and Sushi. Hurley and Costa wanted to look at animals that were diving freely, so she had to train the animals to remain submerged until they reached their aerobic limit. This meant convincing them to sit at the bottom of a pool, and do...
