![]() ![]() They believe that by synchronising their ascent, beaked whales don’t need to talk to each other to regroup- and being quiet is a huge advantage when your predators have a keen sense of hearing. The researchers also found that after a while hunting for prey, the whales regroup and slowly head on to the surface in silence. ![]() As killer whales remain mostly near the surface (max 50m deep), it’s relatively safe to be loud at lower depths. Unlike other deep-diving whales, beaked whales coordinate with other group members when they dive, but when they reach lower depths, they forage separately using echolocation. In the new study, Aguilar’s team found other unique behaviours in Blainville’s and Cuvier’s beaked whales. Also bizarrely, after these deep dives beaked whales do a series of silent shallower dives. Previous research reported vey unusual deep-diving behaviours in these whales: they restrict echolocation to the deepest part of their foraging dives and then ascend slowly and silently, in contrast to most whales, which ascend quickly and nearly vertically. The tags collected depth and orientation data and recorded sound for about 20 hours. They had to slowly approach each of the 26 whales on a small boat and then place the tag on their back with a long pole. To test this hypothesis, Aguilar, Johnson and their colleagues tagged Blainville’s ( Ziphius cavirostris) and Cuvier’s ( Mesoplodon densirostris) beaked whales to track their movement and vocalisations. When we see this through the prism that they might be trying to avoid killer whales… it all kind of makes sense. ![]() Natacha Aguilar de Soto, Mark Johnson and colleagues at the University of La Laguna, Tenerife (Spain) and University of University of St Andrews, Scotland (UK) suspected that the beaked whales’ deep-diving behaviour could have something to do with avoiding killer whales. They regularly dive deeper than 500m to forage for food, but a study reported record-breaking dives nearly 3000m deep and lasting for over two hours!Īlthough deep diving is common among marine mammals, it’s a very costly behaviour because it uses up a lot of energy which large animals can’t afford to waste. Beaked whales, on the other hand, forage alone and communicate with loud clicks, so they can’t use any of these defence tactics.īeaked whales are medium-size teethed whales with a sort of “beak” (hence their name) and an unusual set of (only) two large tusk-like teeth in males. ![]() Many other species, from dolphins to sperm whales, pack together in large groups to protect each other and fight off their predators. For example, toothed whales, which use whistles and clicks (echolocation) to communicate and forage for food, can tune their vocalisations to beyond the hearing range of killer whales, and some baleen whales can “whisper” to their babies. Whales have evolved sophisticated strategies to escape their large-brained predators. Killer whales mostly attack whale calves, but they can also gang up and prey on adult whales quite effectively. So how do these gentle giants avoid getting eaten by predators with sharp hearing and eyesight? New research reveals that beaked whales use a unique silent deep-diving strategy to avoid predation by killer whales.ĭespite their huge size, whales are often on the lunch menu of killer whales, also known as orca ( Orcinus orca). In an empty ocean, even a whale the size of a truck can be prey to vicious predators. ![]()
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