Scientists have long noticed that belugas have a unique ability for cetaceans to change the shape of a special fat pad on their forehead (the so-called acoustic lens, or melon, which serves echolocation). So far, little study has been done on why animals do this. Experts in zoological sciences and veterinary medicine from the University of Rhode Island (USA) undertook to explain this phenomenon.
Researchers studied two pairs of beluga whales (two males and two females) at the Mystic Aquarium in Connecticut (USA) for a year, videotaping their behavior. In addition, zoologists observed three groups of beluga whales of both sexes at Marineland, Canada’s marine animal theme park. As a result, scientists concluded that the change in the shape of the forehead in belugas is a way of visual communication.
Many mammals use facial expressions to convey their emotions and intentions. Cetaceans practically do not have such a possibility: their facial muscles are under a dense skin resembling rubber, which is less elastic than, for example, in dogs or monkeys. However, toothed whales of the species Delphinapterus leucas It seems that they have learned to overcome this obstacle by changing the shape of the melon, developing an alternative to mimicry to provide communicative signals to their relatives.
During observation of beluga whales, researchers recorded 2570 changes in forehead shape. Typically this occurred during interactions with other beluga whales when the animals were in view. The nature of communication can vary from playful and loving to aggressive. Zoologists also noted that males change the shape of the melon three times more often than females.
Scientists have identified five types of changes in the melon’s shape depending on what happens to it: compression, lift, squeezing, protrusion and shaking. Observations have shown that some types of behavior are often combined with one or another shape of the forehead. For example, during mating rituals, belugas would move their heads vigorously, often flattening or shaking a melon.
However, researchers have not yet been able to reliably determine whether beluga whales change the shape of the melon on purpose or if this happens reflexively in conjunction with other habits. Moreover, although scientists have noticed a relationship between behavior and a certain shape of the forehead, they have not yet been able to unravel the exact meaning of these signals.
Studies of American zoologists recently published in the journal Animal CognitionIt is an important step in a more complete understanding of beluga communication. They are highly social animals that use more than 50 different sound signals to communicate: whistles, screams, chirps, clucks, shrieks, shrieks, and even roars. In addition, belugas use “body language” to slap the water with their tail fins.
The study authors concluded that, all things considered, changing the shape of the melon is another type of interaction that is likely related to the mating systems of these highly intelligent marine mammals.
Source: Port Altele
