Cuvier's beaked whales routinely dive beyond 1,000 metres for around an hour to hunt squid, spending the interval between dives at shallow depths. Satellite-linked tags attached off southern California produced two exceptional records: a maximum depth of 2,992 metres and, in a later study of the same population, a single dive lasting 222 minutes.
The physiology is stretched but explicable. Beaked whales collapse the lungs early in descent, store most of their oxygen in blood and muscle rather than in air, carry very high myoglobin concentrations, and slow the heart drastically. The longest dives are outliers rather than routine, and the two record animals had recently been exposed to sonar, which may have altered their behaviour.
The species is also the one most frequently linked to mass strandings during naval sonar exercises. The association is well documented in the Mediterranean and elsewhere, though the physiological pathway from sound exposure to death is still argued over.