Cuvier's beaked whale

The Cuvier's beaked whale, goose-beaked whale, or ziphius (Ziphius cavirostris) is the most widely distributed of all beaked whales in the family Ziphiidae. It is smaller in size than most baleen whales—and indeed the larger toothed cetaceans (like orca and sperm whales)—yet it is large among the beaked whales and smaller cetaceans, appearing somewhat like a bigger and stockier bottlenose dolphin. Cuvier's beaked whale is pelagic, generally inhabiting waters deeper than 300 m (1,000 ft), though it has been observed closer to shore on occasion. In these offshore waters, Cuvier's beaked whale executes some of the deepest, longest recorded dives among whales, and extant mammals, at 2,992 m (9,816 ft), for 222 minutes. While likely diving to forage and hunt prey, such as cephalopods, and potentially evade predators (like the aforementioned orca), the frequency and exact reason for these extraordinary dives is unclear. Despite its deepwater habitat, it is one of the most frequently-spotted beaked whales when surfacing.

Cuvier's beaked whale was named Ziphius cavirostris by Georges Cuvier based on a skull fragment which he believed to be a fossil from an extinct species. He reused the genus name Ziphius from an undetermined species mentioned by historical sources. The species name, cavirostris, comes from the Latin cavus ("hollow") and rostrum ("beak"), and refers to the bony cavity of the nares (nasal bones), now known as the prenarial basin. This feature is now known to be unique to male Z. cavirostrus.