Lonesome dolphin appears to talk to himself, study says. ‘It is highly unusual’

A lonesome male dolphin has surprised researchers by exhibiting a strange behavior: talking to himself.

In 2019, a bottlenose dolphin — nicknamed Delle — took up residence off the coast of Svendborg, Denmark.

Despite the fact that no other dolphins have ever been recorded in the area, he remained there for years, often showing up at the waterfront during the daytime.

Intent on studying Delle, researchers at the University of Southern Denmark placed an underwater recorder in the Svendborg harbor for two months, according to their study, which was published on Oct. 31 in the journal Bioacoustics.

“We expected that he would produce few, if any, communicative sounds in the absence of potential recipients,” researchers wrote. “Contrary to this expectation, we found the dolphin to be highly vocal, emitting burst-pulse and tonal sounds in rhythmic bouts.”

Throughout the course of the study, Delle made three distinct types of whistles, which was uncommon as most dolphins have just one “signature” whistle.

“It is highly unusual that the dolphin produced these sounds” while alone, researchers said.

These sounds — which researchers called “self-talk” — did not have a simple explanation.

Researchers hypothesized, though, that they “may be emitted unintentionally as emotional signals, serve functions other than direct communication, or simply be a byproduct of dolphins’ intrinsic need for social interaction.”

They also noted that self-talk has also been observed in humans, meaning it may be a common phenomenon among social animals.

Not all dolphin experts were taken aback by the findings, though.

“Dolphins are very vocal animals, so I’m not overly surprised that this individual was still making sounds despite being alone,” Thea Taylor, managing director at the Sussex Dolphin Project, told Live Science.

The study authors were Olga Filatova, Ivan Fedutin, Freja Jakobsen, Céline Grandjean and Magnus Wahlberg.

This story was originally published November 19, 2024 at 2:54 PM with the headline "Lonesome dolphin appears to talk to himself, study says. ‘It is highly unusual’."