Why go beaked whales in the stealth mode

25 July 2011 last updated 05: 01 am by Matt Walker, editor, BBC nature Blainville of beaked whales, which are among the world of most enigmatic Cetacea, go quietly in shallow waters.

Researchers have discovered that the whales are refusing to communicate with each other near the surface.

By he quietly, it prevents the whales stealth mode that they detected by predatory killer whales.

The study, one of the first record how beaked whales communicate also recorded sounds made by each mammal in the deepest recorded depth.

Beaked whales are deep diving, toothed.

Little is about them, partially known because they spend so much of their time in the ocean depths.

Some species have been sighted hardly and it awaiting more varieties of the discovery to scientists suspect can Wal.

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keep silence near the surface is an unexpected behavior and striking in contrast with the other toothed "

end quote Dr. Aguilar and gentlemen write in marine mammal science, is very little known about how beaked whales communicate or avoid enemies."

So Natacha Aguilar of the University of La Laguna in Tenerife, Spain and colleagues at the Woods Hole Oceanographic Institution in Massachusetts, us, and University of Aarhus, Denmark, the first study in conducted as beaked whales diving communicate.

With suction cups, the researchers attached electronic bugs on eight Blainville beaked whales, 102 hours total results recording.

Took the noise made by the whales but the water and swim close to the surface of the water, as they came to breathe and also, plunged to the depths of 900 m as they.

The results, published in the journal mammal marine science, showed that the Blainville silence fell beaked whales, as soon as they entered water, the shallower than 170 m.

Above this depth, which does not communicate whales, they were while also silence, as ascending dives: a rise through the water, which last an average of 19 minutes.

This is despite the fact that these whales spend 60% of the swimming shallower waters of life in over 170 metres, and are expected to maintain social bonds, especially as they swim and in diving close knit groups communicate with each other.

When the whales into deeper waters sponge, they sound off.

Orcas swim and hunt closer to the surface

In deep under 450 m, a number of echolocation clicks, interspersed with so-called buzzes, made the whales tonal flutes and short bouts of repeated clicks.

The whales that probably make to navigate the echolocation clicks and chase the prey.

But the pipes and repeated clicks, which researchers dubbed "wax", had never before have been recorded.

The whales they serve could coordinate their movements a dive for the hunting help, on how it at the bottom of dispel.

The researchers believe that in a stealth mode, when swimming in shallow waters of an anti-predator strategy is.

Known as Orcas, shallow divers that affect many whale species in shallower waters are killer whales, better.

Broadcasting its location to Orcas avoid the beaked whales swimming in stealth mode.

Hidden in the oceans an effective prevention can strategy, such as beaked whales not Orcas out swim this way and some other defenses against them.

"For the Blainville beaked whales, that lives in closed groups and coordinate their activities, silence, hold close to the surface, an unexpected behavior and striking in contrast with the other toothed whales," write the researchers in the journal.

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