Zoologists discovered what humpback whale calves "ask" their mothers for.

Researchers have long been fascinated by the vocal repertoire of whales. Previous studies indicated that sequences of repetitive sounds at varying frequencies, commonly referred to as whale songs, are used in courtship displays, for communication with peers, navigation, and other purposes. It is also known that whales have the ability to remember and accurately reproduce each other's songs.

Such scientific works have often focused on the vocalizations of adult animals. In a new article recently published in the journal Proceedings of the Royal Society B: Biological Sciences, the authors shifted their attention to the acoustic communication of humpback whale calves (Megaptera novaeangliae).

Specialists observed the behavior of eight calves living with their mothers near the island of Nosy Boraha (formerly St. Marie) off the coast of Madagascar. For this purpose, special cameras equipped with sensors capable of capturing audio and video data were attached to the calves. The recordings, totaling over 30 hours, formed the basis of the study.

During the analysis, the scientists separated about 500 vocalizations of the calves from other sounds, including those made by their mothers, and examined the contexts in which they occurred. This allowed them to identify common patterns and categorize the vocalizations into several groups based on the activities of the calves—whether they were feeding, playing, or simply swimming.

The calves vocalized less frequently during rest and calm movement, while during play at the water's surface, they became noisier, producing mid-frequency sounds resembling calls.

Additionally, the calves actively "called out" before their morning feeding on maternal milk. During this time, they produced distinctive low-frequency sounds that the authors described as "snorts, barks, grunts, and belches." The researchers noted that these characteristic sounds had previously been recorded in calf vocalizations, but this is the first time they have been associated with feeding.

The scientists believe that the calves are thus communicating with their mothers to request food. Similar behavior can be observed in the young of terrestrial mammals, but it has not been documented in humpback whales before.

The study revealed new insights into the behavior of humpback whales and provided a better understanding of the communication systems among marine mammals in the "mother-calf" pair, concluded the specialists.