The scientists traveled to Hawaii and joined Terrie Williams at the Navy's lab. There they tested three male dolphins and found the region around the testes was 1.3 degrees cooler than the surrounding body. Soon afterward, Pabst and McLellan realized female dolphins had an even more desperate need than males did for a cool core - their wombs. A female dolphin can't do that on dives. The uterus is in the same part of the body as the testes.
Female dolphins use the same anatomical trick that males do.
Last summer, when Pabst and McLellan measured wild dolphins off North Carolina, one pregnant subject registered the coldest temperature ever measured inside a dolphin. Pabst hopes to pursue this question soon by studying blood flow in female dolphins after a long dive. Because they also have the ability to outperform their aerobic capacity, dolphins are in the company of some highly efficient land animals, like kangaroos. But even after their oxygen consumption leveled off, dolphins kept pushing against the sensor. During this so-called anaerobic behavior, humans build up lactic acid, diminishing their capacity to continue.