Every winter, the beaches of central California become a battleground. Male northern elephant seals rise up, clash chest to chest and send their roars across the sand in battles that determine rank, territory and access to mates. This is one of the loudest and most violent spectacles in the animal world.
But when the same males return the following year, do past battles fade with the season—or do they remain a memory?
Now a team of researchers has discovered that these confrontations are shaped not just by size and strength, but also by memory. Male elephant seals can recognize the calls of rivals they have encountered in the past year and adjust their behavior accordingly. By sound alone, they seem to remember who once dominated them and who they defeated, determining whether they will retreat, challenge, or hold their ground.
“Male elephant seals return to the same breeding site year after year and engage in competitive interactions with a range of familiar individuals,” Caroline Casey, who led the team, said in the report. press release. “Then it would make sense for them to retain some memory of past rivals over several seasons.”
Vocal calls of elephant seals
Male northern elephant seals produce calls with a characteristic rhythm and tones that allow others print recognize them as individuals. Over time, their voices become tied to personality—so much so that researchers compare them to names, according to reports in Nature.
This vocal identity is most important during the breeding season, when the beaches fill with hundreds of large males competing for dominance and access to mates. Animals starve for weeks, relying on stored fat, and because physical fights involve so much energy expenditure and injury, many conflicts are avoided before they escalate, according to earlier behavioral studies published in Open Science.
Instead of settling every dispute by force, seals often rely on sound. Through their calls, males broadcast their status as well as their personality. A familiar, dominant voice can discourage opponents before the fight even begins, and calling out a weaker opponent can provoke a confrontation. The fine structure of these identity signals was mapped in a 2017 study. Current biologywhich showed that seals not only detect aggression when calling, but also recognize specific individuals.
Read more: Are leopard seals as dangerous as you think?
Testing memory sealing using recordings
To test whether these vocal features persisted after one breeding season, the team turned to playback experiments. Early in the season, they detected returning males and played back recorded calls of rivals the seals had encountered the year before. Some recordings were made by dominant competitors, others by subordinates, and still others by unfamiliar males from distant colonies.
“When males heard their most familiar dominant rival in the previous year, they tended to orient themselves more quickly, change posture more quickly, and often retreat from the speaker,” Casey said. “Their responses were less harsh when presented with a subordinate opponent from the previous season, and sometimes they even approached the speaker.”
When the team played unfamiliar voices recorded in other colonies, the sounds did not provoke much of a reaction. The seals did not respond to random strangers or general threat signals – they recognized and remembered specific people they encountered the year before.
What does an alpha do?
Researchers are now turning their attention to traits that lead to reproductive success.
“We're working on a project right now to evaluate the traits that lead to the ultimate reproductive success of male elephant seals,” Casey said. “Essentially, what does it take to become an alpha seal? We measure many different aspects of behavior and physiology and relate that to the true reproductive success of the species.”
Read more: How can seals hold their breath for an hour or more?
Sources of articles
Our authors in discovermagazine.com use peer-reviewed research and high-quality sources for our articles, and our editors review scientific accuracy and editorial standards. Review the sources used below for this article:
