アカボウクジラ
In 2014, scientists reported that they had used satellite-linked tags to track Cuvier's beaked whales off the coast of California, and found that one animal dove up to 9,816 feet (2,992 m) below the ocean surface, which represents the deepest dive ever documented for any mammal. Another study, published in 2020, reported a Cuvier's beaked whale making a dive that lasted 222 minutes, which represents the longest dive ever documented for any mammal. Supervising scientist Nicola Hodgkins noted that "the recorded dive-time of more than three hours is likely not typical, and instead the result of an individual pushed to its absolute limits". Exposure to high noise levels from a nearby military sonar is likely to have caused the abnormal behavior.