The world’s most powerful clickbait?

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The world’s most powerful clickbait?

Male sperm whales produce the loudest communication sounds ever measured in any mammal. These are loud clicks that the whales emit in an extremely precise and slow rhythm that can potentially be heard up to 70 kilometres away.

A research team led from Aarhus University has revealed that male sperm whales produce extremely loud clicks in surprisingly precise and slow rhythms. The next step is to find out what they use the slow clicks for.

Photo:<br>Tim Cole, National Oceanic and Atmospheric Administration

200 dB re 1 µPa (pp), making them the loudest mammalian communication signal, with an estimated active space of ∼70 km. Slow clicks are highly rhythmic at rates of 0.1−0.3 Hz (ICI = inter-click Intervals), which is an order of magnitude slower than other rhythmic communication signals among mammals and birds." class="lightbox" rel="lightbox[myImageSet]">

The study shows that male sperm whales produce low-frequency slow clicks at low repetition rates with extreme source levels > 200 dB re 1 µPa (pp), making them the loudest mammalian communication signal, with an estimated active space of ∼70 km. Slow clicks are highly rhythmic at rates of 0.1−0.3 Hz (ICI = inter-click Intervals), which is an order of magnitude slower than other rhythmic communication signals among mammals and birds.

Photo:

Simone Videsen

Slow clicks from a male sperm whale, recorded with a hydrophone from a boat off the Seychelles.

Professor Peter Teglberg Madsen attaches a suction cup sound recording tag to the back of a sperm whale off the Azores. Please click the “dotted” square to view the video in full size.

Photo:

Cláudia Oliveira

5 August 2026

by

Peter F. Gammelby

Deep in the world’s oceans, the large male sperm whales emit slow, low frequency clicks with the highest source levels of any animal communication sounds.

These slow clicks are not echolocation clicks the whales otherwise use to locate prey, but instead loud, low frequency communication signals.

This is the conclusion of an international research team that has measured and analysed the slow clicks in waters off the Seychelles, Sri Lanka, Norway and Scotland. The project is led from Aarhus University, more specifically from Zoophysiology at the Department of Biology.

Their research suggests that male sperm whales use a kind of reverse clickbait. It is not bait designed to make someone click. The click itself may be the bait.

Whether the clicks are in fact the whales’ version of “look at me!” to females, “keep away!” to other males – or something else entirely – the researchers do not yet know. But they have plans to find out.

A metronome in the ocean

Sperm whales are famous for their clicks. They use clicks to find squid in the dark at great depths by echolocation, and also use short rhythmic click packages, known as codas, in their social communication.

But these slow clicks are different.

As far as the researchers know, they are produced exclusively by males. They are slower, lower frequency and more powerful than the social coda clicks. There can be five to ten seconds between each click. Even so, the whales keep the rhythm with a precision comparable to a drummer playing very, very slowly.

This surprised the researchers.

“What is extreme about slow clicks is that the whales can produce them with long time intervals between them. And they can do it very rhythmically. And over those distances. It is really the combination of the three things that is extreme: the strength, the rhythm and the range,” says Simone Videsen, a postdoc at Zoophysiology at the Department of Biology, Aarhus University.

She is first author of the study, which has just been published in the respected scientific journal Annals of the New York Academy of Sciences.

A five-ton nose

The reason the sperm whale can make such powerful clicks lies in its highly unusual anatomy.

The male has the world’s largest sound-producing organ: a gigantic nasal complex, which in a fully grown animal can weigh more than five tonnes and makes up about one third of the body length.

This is where the so-called phonic lips are found. These are car tire sized structures in the nose that the whale snaps together to create clicks.

“A big nose sits on a big male, and a big nose will produce a lower-frequency click. That makes slow clicks interesting, because the clicks may tell us something about the male producing them. The sound may therefore function as an honest signal of size – what we biologists call honest advertisement,” explains Professor Peter Teglberg Madsen, a senior-author of the study and from the same department at Aarhus University.

In other words: if a male sperm whale clicks at a low pitch and high volume, it may tell both females and rivals that here comes a large male worth paying attention to.

But that is still...