Nav: Home

Elephant seals recognize each other by the rhythm of their calls

July 20, 2017

Every day, humans pick up on idiosyncrasies such as slow drawls, high-pitched squeaks, or hints of accents to put names to voices from afar. This ability may not be as unique as once thought, researchers report on July 20 in Current Biology. They find that unlike all other non-human mammals, northern elephant seal males consider the spacing and timing of vocal pulses in addition to vocal tones when identifying the calls of their rivals.

"This is the first natural example where on a daily basis, an animal uses the memory and the perception of rhythm to recognize other members of the population," says first author Nicolas Mathevon, of the Université de Lyon/Saint-Etienne in France. "There have been experiments with other mammals showing that they can detect rhythm, but only with conditioning."

Over several years studying an elephant seal colony in Año Nuevo State Park, California, the researchers were able to recognize many of the individual animals just by the rhythm of their voices, he says. To test whether the elephant seals themselves made those distinctions in the same way, the researchers designed an experiment based on the social behavior of the colony's "beta males," who shy away upon hearing the call of a more powerful "alpha male" but ignore or confront other beta males and still-weaker "peripheral males."

Upon hearing computer-modified alpha male calls with a sped-up or slowed-down tempo or a shifted pitch range, the beta males fled the scene if the alteration was minute enough to be within the individual variation of a particular alpha male's roar but stayed put when confronted with more extreme changes. The divergent responses indicated that the seals were sensitive to both rhythmic and tonal characteristics when identifying potential rivals within the colony.

"It is possible that maybe the ability to perceive rhythm is actually very general in animals," Mathevon says, "but it's extremely important for elephant seals, to the point of survival. Competing for females, the males fight very violently, even to the point of killing one another. So it's very important for them to accurately recognize the voices, to be able to choose the right strategy, to know to avoid a fight with a dominant male, or even to start a fight with an inferior one."

Rather than solely using tempo to identify specific calls, the northern elephant seal may even be able to parse rhythm at a finer level, says Mathevon. Different individual seal calls include elements such as single, double, or burst pulses, much as a human musician might divide a single beat into one long note, two shorter notes, or a frenzy of slides and trills. The researchers hope that future work will reveal whether elephant seals might also be able to distinguish calls at this further level of rhythmic complexity.
-end-
This work was supported by the U.S. Office of Naval Research, the Centre National de la Recherche Scientifique, the Université de Lyon/Saint-Etienne, the University of California, Santa Cruz, and the Université Paris-Sud.

Current Biology, Mathevon et al.: "Northern Elephant Seals Memorize the Rhythm and Timbre of Their Rivals' Voices" http://www.cell.com/current-biology/fulltext/S0960-9822(17)30772-8

Current Biology (@CurrentBiology), published by Cell Press, is a bimonthly journal that features papers across all areas of biology. Current Biology strives to foster communication across fields of biology, both by publishing important findings of general interest and through highly accessible front matter for non-specialists. Visit: http://www.cell.com/current-biology. To receive Cell Press media alerts, contact press@cell.com.

Cell Press

Related Seals Articles:

TV crews capture first evidence of leopard seals sharing food
Previously unseen footage captured during filming for the Netflix series Our Planet -- narrated by Sir David Attenborough -- reports up to 36 seals seen feeding at the same king penguin colony in South Georgia.
Mapping Oregon coast harbor seal movements using wearable devices
Wearable devices fitted to harbor seals reveal their movements around the Oregon coast, for a population that has been increasing following the implementation of marine reserves and protection acts.
Wearable device reveals how seals prepare for diving
A wearable noninvasive device based on near-infrared spectroscopy (NIRS) can be used to investigate blood volume and oxygenation patterns in freely diving marine mammals, according to a study publishing June 18 in the open-access journal PLOS Biology by J.
Antarctic biodiversity hotspots exist wherever penguins and seals poop
Scientists have found that on the desolate Antarctic peninsula, nitrogen-rich poop from colonies of penguins and seals enriches the soil so well that it helps create biodiversity hotspots throughout the region.
Chemical records in teeth confirm elusive Alaska lake seals are one of a kind
Lifelong chemical records stored in the canine teeth of an elusive group of seals show that the seals remain in freshwater their entire lives and are likely a distinct population from their relatives in the ocean.
More Seals News and Seals Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Erasing The Stigma
Many of us either cope with mental illness or know someone who does. But we still have a hard time talking about it. This hour, TED speakers explore ways to push past — and even erase — the stigma. Guests include musician and comedian Jordan Raskopoulos, neuroscientist and psychiatrist Thomas Insel, psychiatrist Dixon Chibanda, anxiety and depression researcher Olivia Remes, and entrepreneur Sangu Delle.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...