Rorquals, which are more streamlined than other baleen whale families, are known for attaining the fastest speeds of baleen whales. Other species travel at slower speeds. Baleen whales are not known to dive regularly to great depths. Many species feed in relatively shallow areas of the continental shelf. Dives last anywhere from 3 to 20 minutes or more depending on the species.
All marine mammals have special physiological adaptations during a dive.
These adaptations enable a baleen whale to conserve oxygen while underwater. Baleen whales, like other mammals, have a slower heart rate while diving. When diving, blood is shunted away from tissues tolerant of low oxygen levels toward the lungs, heart, and brain, where oxygen is needed. Compared to terrestrial mammals, baleen whales have twice the concentration of red blood cells and up to nine times the concentration of the oxygen-binding protein myoglobin. Myoglobin and red blood cells store oxygen and provide tissues with oxygen while the whale dives.