Ringtones of the Ocean: How Beluga Whales Use Unique Calls to Contact Each Other
We humans are all very familiar with the sound of a ringing telephone. We frequently receive calls from friends, family, and strangers, and the advent of modern cellphones has allowed us to assign distinctive ringtones to specific individuals. With these ringtones, we can identify our caller before even glancing at the phone screen. What if I told you that humans and our manufactured ringtones are not all that unique? Beluga whales can also produce their own “ringtones” in dark, murky ocean waters, giving way to enhanced communication and group cohesion. Let’s explore more.
Communication is extremely important in all beluga whales, who live in highly complex social groups. Effective vocal communication systems are particularly crucial, as visual signals are often obscured in the dark waters that many belugas call home. Imagine you are swimming in the deep, murky ocean, and your friend, who may be yards away, tries to get your attention by rapidly waving their hands. You would likely miss their frantic gestures. Belugas are no different in that visual signals are often of little value unless the whales are in proximity of one another. Instead, these fascinating creatures produce an impressive array of vocalisations, ranging from whistles and clicks to long, harmonious “songs” that can be easily transmitted through water. Different types of calls have different meanings and therefore different functions. One series of clicks may be used to find food through echolocation, while another series of whistles might function as an alarm call, as if the whale were calling, “Swim fast! There’s a pod of orcas over there!” One specific call, which is composed of a series of pulsated noises transmitted through a wide range of frequencies, is of particular interest to researchers. This is the contact call. It is hypothesised that contact calls are used for individual and group recognition, similar to how humans give each other distinct names. These calls may be specific to an individual, meaning each beluga has a different call, or they may be group-specific, where a beluga uses a contact call similar to or identical to others within its social group. Contact calls are distinct from other types of vocalisations in their frequency, duration, and composition, making them easily discernible. They have been observed when individuals are in isolation, indicating the whales are searching for other belugas.
Contact calls have previously been identified in pods of other species of toothed whales, including bottlenose dolphins and orcas, as well as in mother-calf interactions in beluga whales. Researchers E. Panova and A. Agafonov were curious if pods of all-male belugas also utilised contact calls as sources of individual recognition. To answer this question, the team of researchers placed a recording device at the bottom of Russia’s Varzuga River, where the river empties into the White Sea. This region serves as a breeding ground for pods of mostly male belugas, who gather in early autumn to feed on salmon. If contact calls are indeed used to recognise individuals, it is expected that each individual should have their own unique, discernible call, just as we all have distinct names, or ringtones that could be designated to one individual. If this is indeed the case, researchers reasoned that the number of distinct calls found on the audio recordings should match the number of observed individuals in the region. To determine approximately how many belugas inhabited the mouth of the Varzuga River, the team set up stations along the river and, using binoculars, counted the belugas they observed. After recording ten hours of beluga whale activity across ten days, researchers combed through audio recordings for contact calls. They differentiated contact calls from other beluga vocalisations on the audio by defining the distinct characteristics of a contact call, including duration, frequency, and exchange rate, prior to observation.
The researchers found that contact calls accounted for over half of all vocalisations on the audio recording, suggesting that these calls are indeed prevalent in all-male groups. Furthermore, the number of individual belugas closely matched the number of distinct types of contact calls, which indicates that each beluga has its own unique, identifiable call. The calls differed in whether they were composed of tonal, pulsated, or noisy vocalisations. Using this information, we can think of the contact call as a sort of specific ringtone that you assign to a friend. When you hear a particular jingle, you know which friend is calling you. Beluga whales, when they need to “call” a friend in the ocean, produce their own ringtone to say, “Hello, this is who I am!” Contact calls, then, are the ringtones of the ocean.
Works Cited
Morin, H. (n.d.). Specialized Sounds in Cetacean Communication. Discovery of Sound in the Sea. https://dosits.org/animals/advanced-topics-animals/specialized-sounds-in-cetacean-communication/
Panova, E., Agafonov, A. (2023). Possible Occurrence of Contact Calls in All-Male Groups of Free-Ranging Beluga Whales. Journal of Zoology, 320(1), 29-41. https://doi.org/10.1111/jzo.13054
