Bottlenose dolphins generally do not need to dive very deeply to catch food. They are, however, capable of diving to some depth. It is possible for a dive to last eight to ten minutes.
All marine mammals have special physiological adaptations used during a dive.
These adaptations enable a dolphin to conserve oxygen while it is under water. Dolphins, like other mammals, have a slower heartbeat while diving. When diving, blood is shunted away from tissues tolerant of low oxygen levels toward the heart, lungs, and brain, where oxygen is needed. The muscle of bottlenose dolphins has a high content of the oxygen-binding protein myoglobin. Myoglobin stores oxygen and helps prevent muscle oxygen deficiency.