Cuvier’s beaked whales (Ziphius cavirostris) just shattered their own deep-diving record—as well as that of elephant seals, which were the previous record-holders. The little-known species of beaked whales, cigar-shaped cetaceans with prominent snouts and which range from tropical to northern temperate seas, has long been considered one of the most extreme divers in the ocean, capable of reaching a depth of 1888 meters and staying below for 95 minutes. But a new study that tracked eight individuals off the coast of southern California via satellite tags, as in the photo above, shows they can do much more. (Male Cuvier’s beaked whales have tusks, and the scars on the back of the male in the photo are from fighting with other males.) One whale dove to 2992 meters below the surface, breaking the deep-dive record of a southern elephant seal that was tracked to 2388 meters. Another Cuvier’s beaked whale in the study remained below the surface for 2 hours and 17 minutes. Unlike elephant seals and deep-diving sperm whales, which remain at the surface for an extended period after their dives, the beaked whales headed back into the depths less than 2 minutes later, the scientists report online today in PLOS ONE. The beaked whales in the study made their deep dives about seven times a day, foraging for squid and fish; they spent more time at the surface at night. By better understanding this species’ diving behaviors, the scientists hope to solve an ongoing mystery: Why are Cuvier’s beaked whales particularly sensitive to military sonar operations? Sixty-nine percent of all recorded strandings of marine mammals that were associated with such operations involved this species. Yet these eight whales were tagged and followed on a U.S. Navy sonar training range, leading the scientists to suggest that Cuvier’s beaked whales in this area may have adapted to human noise—perhaps, in part, by becoming the most extreme of extreme divers.
Thanks to Dr. Rajadhyaksha for bringing this to the attention of the It’s Interesting community.