Ending the year with a more captivating sea creature story than the infamous “Russian spy whale” seemed unlikely, yet nature has once again proven that it's wonderfully unpredictable. Five years ago, an unusual creature began roaming the waters off Denmark’s coast, prompting researchers to attach a microphone to uncover its secrets.
A “different” dolphin. The 17-year-old bottlenose Dolphin, which locals named “Delle,” was first spotted roaming the Svendborgsund channel. This area is uncommon for his species, which typically inhabits warmer waters and thrives in social groups called pods. Unlike his peers, Delle has lived in isolation for years.
The “talking” dolphin. Between December 2022 and February 2023, researchers from the University of Southern Denmark studied Delle’s vocalizations. Over three months, they recorded 10,833 sounds, including 2,239 whistles, 5,487 low-frequency sounds, 767 percussive noises, and 2,288 rapid pulses, often linked to aggression in herds.
However, Delle’s vocalizations didn’t seem aggressive. Instead, researchers believe he may be engaging in a form of “self-talk,” potentially reflecting a need for social interaction after years of solitude.
Complexity of sounds. The recordings revealed an intricate array of vocalizations. These could be involuntary emotional signals, attempts at internal communication, and simply the result of his social instincts. While the exact meaning of the sounds is unclear, their persistence and variety underscore the importance of social interaction for dolphins.
Remarkably, Delle developed three distinctive whistles—sounds dolphins typically use to identify themselves, much like names. Most dolphins have only one of these whistles, making this behavior highly unusual. He continued emitting these complex sounds even in the absence of humans or other animals nearby.
Why does he do this? Experts have several hypotheses for Delle’s behavior. Initially, they believed he might be trying to communicate with humans or attract other dolphins. But his persistent solitude and vocalizations without external stimuli led researchers to rule out those theories.
The dolphin that talks to himself. Instead, the most plausible explanation is that Delle’s sounds are involuntary emotional responses, akin to humans laughing alone at a memory. Another possibility, even more intriguing, is that Delle engages in “self-talk,” a behavior associated with prolonged isolation in humans.
However, the researchers said this phenomenon isn’t fully understood in humans or animals. Since this is the first time self-talk has been detected in dolphins, experts have little precedent to guide their understanding.
The mystery of animal solitude. The unanswered question remains: Why is Delle alone in the Baltic Sea? Was he rejected by his pod? Did he lose his way? The reasons for his isolation are unknown, leaving room for speculation.
Despite their intelligence and social nature, dolphins can adapt uniquely to solitude. Researchers have ruled out the idea that Delle is vocalizing to attract other dolphins, given his years-long isolation in an area devoid of his species.
Loneliness in dolphins can lead to more disruptive behavior. In Japan, for example, a solitary dolphin is believed to be behind a series of attacks on swimmers, seemingly seeking attention. In Delle’s case, his vocalizations appear to serve as a way to entertain himself or cope with loneliness.
Animal complexity. Although the solitary dolphin case may offer a unique window into understanding how dolphins cope with loneliness, researchers caution against drawing direct comparisons between human and dolphin behavior. While self-talk in humans and Delle’s vocalizations might seem similar, significant differences exist in how each species communicates and experiences emotions.
Is Delle laughing, crying, or simply trying to fill the silence of isolation? Scientists may never fully understand the meaning behind his sounds. Still, his story underscores the complexity of social life in animals and their resilience in extreme circumstances. For now, the mystery of Delle remains.
What if he simply chose to be alone?
Image | JIMMY ZHANG (Unsplash)
View 0 comments