Very seldom seen at sea, almost everything known about Cuvier's beaked dolphin is based on studies of stranded animals (2) (5) (7). Consequently very little is known about the behaviour and ecology of this elusive species. Nonetheless, recent studies using digital tags are beginning to shed light on its extraordinary foraging habits. In particular, this species has been recorded diving to depths of nearly 1,900 metres, the deepest dives ever reported for any air-breathing mammal. Leaving the surface for up to 85 minutes at a time, the whales use echolocation to hunt prey in the lightless depths (6). Very little analysis has been undertaken on the stomach contents of this species, but deep sea-squid are thought to be the main source of food, with fish, and, to a lesser extent, crustaceans, also being taken (1) (2) (5). Although often seen alone, groups of two to seven whales are most common (5) (7). Its inconspicuousness at sea is jointly attributed to its low, diffuse blow and its tendency to avoid vessels (2). The lifespan of Cuvier's beaked whale is thought to be at least 25 years (5).