Just like humans, many animals rely on social interactions to survive and thrive. As a result, effective communication between individuals is essential.
Highly social species tend to develop more complex communication systems. Think of chimpanzees using gestures and vocalizations, or elephants exchanging information through touch and low-frequency calls.
Bottlenose dolphins live in complex social structures, where each individual maintains a small group of close companions and a broader network of more distant acquaintances — a social pattern not unlike our own. To sustain this balance, dolphins heavily depend on social interactions.
Researchers have long known that these dolphins use unique “signature whistles” to identify themselves to others. However, a recent study suggests that these sounds may carry more than just identity information.
A Unique, Yet Flexible Sound
Dolphins communicate using various sounds, including burst pulses and whistles. These whistles are generally divided into two types: signature whistles, which are unique to each individual, and non-signature whistles.
Dolphins develop their signature whistles at a young age and retain them throughout their lives. These whistles have distinct frequency patterns that act like a vocal name.
During interactions with others, up to 30% of a dolphin’s whistles may consist of its signature whistle. Despite being individualized, these sounds often vary slightly. This led researchers to investigate the balance between stability and variation — and whether this combination might transmit additional information beyond identity.
Studying the Sounds
Between 2017 and 2018, a team of researchers recorded sounds from a group of Indo-Pacific bottlenose dolphins (Tursiops aduncus) near Tangalooma Island Resort, off Moreton Island near Brisbane, Australia.
They recorded numerous instances of the same dolphins producing their signature whistles and also analyzed data collected from the same group 15 years earlier.
They found that while the frequency patterns were remarkably stable, the whistles did exhibit some variation — and this variation remained consistent over time. This suggests that although these patterns communicate identity, they likely also convey other information, such as emotional states or context.
Although the sample size was small, the study indicated that males showed more variability in their signature whistles than females — possibly due to differences in social roles and interaction styles.
The researchers also identified a whistle similar to a signature type that was shared by several dolphins — supporting previous findings that groups may have shared whistles alongside their individual ones.
Whistles That Work Like Faces
So, what does all of this mean?
First, signature whistles may be more versatile than previously believed. Their frequency patterns — and possibly their structure — seem to encode additional information.
Secondly, while signature whistles are learned individual “labels” similar to human names, they may function more like “auditory faces” in the way they transmit information.
Humans convey identity through the fixed features of our faces, but we also communicate emotions and context through changing facial expressions. In a similar way, signature whistles combine stable and variable elements to deliver a broader message.
When the World Goes Quiet
Understanding how dolphins communicate helps us grasp the challenges they face in oceans increasingly impacted by human activity.
One such challenge is ocean noise pollution — a growing concern for marine bioacoustics researchers, though not often top of mind for the general public.
When we think about noise, we usually consider how it affects humans. For us, a noisy environment can be irritating and stressful, but we can still function.
For dolphins, however, loud ship noise would be like the world suddenly going blurry. Imagine trying to navigate life, make friends, avoid danger, and maintain social connections — all without being able to recognize faces or see expressions.
If we think of dolphins’ signature whistles as the auditory equivalent of human faces, we may begin to better see — and hear — the world from a dolphin’s perspective.
Read the original article on: Scince Alert
Read more: Google AI May Be Close to “Speaking Dolphin” with New DolphinGemma Model
