Groups of beaked whales dive in SILENCE to depths of around 1,500ft to avoid killer whales

Beaked whales have developed a unique way to avoid being hunted down by killer whales — they silently dive in groups to depths of around 1,500ft (450m). 

This takes them out of range of predatory orcas and allows them to reach the safety of deep waters, lowering the chance of being caught and killed to less than 25 per cent. 

They then use vocalisations and echolocation to hunt for food independently before rendezvousing at depths of 2,500ft (750m) and slowly climbing to the surface.

Experts say this behaviour has not been observed in other deep diving whales and the reasons for it are still a mystery. 

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Beaked whales have developed a unique way to avoid being hunted down by killer whales — they dive down in silent groups to depths of around 1,500ft (450m). This takes them out of range of predatory orcas and allows them to reach the safety of deep waters

Scientists analysed data from 26 beaked whales carrying sensors that tracked the depths they swam to, the steepness of their dives, and the sounds they made. 

The researchers from University of La Laguna in Spain noticed the marine mammals keep quiet in shallow waters. 

They write in their study, published today in the journal Scientific Reports: ‘Biologging data from 14 Blainville’s and 12 Cuvier’s beaked whales show that group members have an extreme synchronicity, overlapping vocal foraging time by 98 per cent despite hunting individually, thereby reducing group temporal availability for acoustic detection by killer whales to <25 per cent.’ 

Experts say this behaviour has not been observed in other deep diving whales and the reasons for it are still a mystery

Scientists analysed data from 26 beaked whales carrying sensors that tracked the depths they swam to, the steepness of their dives, and the sounds they made

They speculate this is to avoid drawing the attention of predators, such as killer whales. 

After successfully reaching the deep water, the whales then go off and hunt independently before gathering to ascend. 

But their trip to the top takes a shallow trajectory, as they climb slowly. 

Researchers say that on average, the return trip can see them emerge around 0.6miles (one kilometre) away from where they started. 

But this ascension strategy, although cautious, comes at a cost to the whales. 

They can take more than an hour to complete and reduces foraging time by around 35 per cent.  

Researchers say the findings suggest predation risk may have been a strong evolutionary force driving the unique diving and vocal behaviour of beaked whales. 

WHAT DO WE KNOW ABOUT BEAKED WHALES?

Beaked whales are members of the family Ziphiidae, the second largest family of cetaceans – which includes whales, dolphins and porpoises.

Many of the 22 species of beaked whales are among the least known or understood mammals in the world.

So rarely are they seen in the wild that three new species of beaked whales have been discovered in just the last two decades.

Living in deep waters, usually far offshore, these creatures spend 92 per cent of their time underwater. 

Beaked whales break diving records, feeding at depths that can reach almost two miles deep (three kilometres) and last up to two hours.

True’s beaked whales are members of the family Ziphiidae, the second largest family of cetaceans – which includes whales, dolphins and porpoises. Many of the 22 species of beaked whales are among the least known or understood mammals in the world (stock)

After these diving feats, they rest, performing shorter and shallower dives with brief surfacing intervals. 

These behaviours, combined with the fact that they live in small groups, are not usually attracted to boats, and do not perform aerial acrobatics as much as dolphins, mean that beaked whales are not easy to detect at sea.

Many beaked whales also share colour patterns with other ziphiid species, making identification of the whales difficult during sea encounters when often only a short glimpse of their bodies is available.

They are found in two geographically distinct areas, and these populations may soon be separated into two subspecies or even separate species.

Positive identification at sea is extremely difficult and in the northern reaches of the range it can be virtually impossible without a clear view of the head (of males only), to distinguish between a True’s and a Gervais’ beaked whale.