During so-called drift dives, an animal spends a proportion of the dive not moving, suspended in the water column while drifting up- or downwards, depending on its buoyancy. Roles of drift dives are believed to include resting, sleeping, or digesting food, which are important components in at least some species' activity cycles. Drift diving was first documented in both species of elephant seals, Mirounga angustirostris and M. leonina and later other pinnipeds such as New Zealand fur seals and hooded seals. Drift dives also occur in cetaceans such as sperm whales and humpback whales. Herein, Blackwell et al describe the presence of drift dives in a bowhead whale (Balaena mysticetus) and hypothesize about their role.