Marine biologists are perplexed by the lone bottlenose dolphin's vocalizations, because some resemble sounds typically used for communication

The only dolphin in the Baltic Sea seems to like muttering to himself. Researchers are trying to figure out why.

Affectionately named Delle, a male bottlenose dolphin, has become an unexpected resident of the Baltic Sea, far from his species’ usual warm and bustling habitats. His unusual presence near Denmark’s Svendborgsund channel has intrigued marine biologists and captivated local communities,

When you are alone, especially for long periods of time, do you talk to yourself? If so, you’re in interesting company because a male Atlantic bottlenose dolphin who has been living alone in the Baltic Sea for more than three years, appears to be talking to himself.

What happens when a highly social creature like a bottlenose dolphin is left utterly alone? Delle, a solitary dolphin in Denmark, may be showing us.

A solo traveler off the coast of Denmark is apparently screaming into the void, revealing the importance of social interactions for dolphins.

The researchers listened in on Delle with an underwater microphone for 69 days, between December 8, 2022, and February 14, 2023. Though they initially weren’t expecting much, the researchers say they detected communicative sounds in 35 out of the 69 days.

A solitary dolphin in the Baltic Sea has been recorded talking to himself, leading researchers to wonder whether he's lonely and calling out for friends.