Aquarium Belugas Have Playful Mouth-to-Mouth Interactions

Within the animal kingdom, physical contact makes up a vital modality of social interaction. For mammals, a diverse array of social contact types exists, including affiliative contact (e.g., nuzzling, rubbing, holding), maternal-infant contact, sociosexual contact, social grooming, and aggressive contact (e.g., biting, scratching, wrestling). These behaviors present distinct forms and functions. Mother-infant contact, for instance, encompasses maternal behaviors that foster social bonds and development during the initial year of an infant's life. Remarkably, many animal species rely upon social contact as an essential aspect of their existence. It facilitates the consolidation of bonds within their social groups and mediates conflicts. Juvenile bottlenose dolphins exemplify this, as they engage in sociosexual contact, often leading to enduring bonds.

A 2023 article published in the peer-reviewed journal Zoo Biology highlights the diverse play behaviors of beluga whales, focusing on their intriguing social play involving mouth-to-mouth interactions. These playful encounters involve two belugas approaching each other head-on, interlocking their jaws, and clasping each other, resembling a handshake. This behavior has been observed in both wild and captive settings and is believed to serve as an essential form of social play, facilitating socialization among the whales.

It is important to note that cetaceans are highly tactile creatures and commonly interact through various forms of fin and body contact. Toothed whales, for instance, engage in pectoral fin rubbing to mitigate conflict and strengthen social bonds. Additionally, they may use their mouths in both aggressive and affiliative ways, including raking and gentle mouthing. However, the unique mouth-to-mouth interactions have received the least scientific attention, making them a subject of ongoing research and fascination.

Beluga whales are not singular among cetacean species in engaging in mouth-to-mouth interactions. Several other species have been observed exhibiting this behavior. For instance, killer whales under human care engage in mouth-to-mouth tongue-touching to solidify their social bonds. Mutual mouth contact has also been documented among Atlantic bottlenose dolphins both in their natural habitat and in captivity. Furthermore, Yangtze and East Asian finless porpoises have been observed engaging in mouth-to-mouth interactions while under human care. Despite these playful observations, a comprehensive study on these interactions is yet to be undertaken.

An extensive investigation spanning twelve years, from 2007 to 2019, was undertaken to gain insights into an intriguing and playful behavior observed in captive beluga whales. Researchers engaged in systematic observation of a group of belugas, starting from their early developmental stages, to comprehend the patterns and preferences associated with their mouth-to-mouth interactions.

The study yielded noteworthy findings, showing that both male and female belugas engaged in mouth-to-mouth interactions with comparable frequencies. However, significant differences were observed in their preferences regarding interaction partners. Male belugas showed a pronounced predilection for interacting with other males, whereas female belugas exhibited a preference for interacting with other females.

Furthermore, the research team discerned a distinctive pattern in the frequency of mouth-to-mouth interactions throughout the belugas' lifespan. These interactions reached their zenith during the early years of life, subsequently undergoing a gradual decline as the belugas matured and advanced in age.

This research endeavor underscores the paramount significance of distinctive behaviors, notably those encompassing cooperative skills that cause both social and motor proficiencies, exemplified by mouth-to-mouth interactions. It provides insightful perspectives into the roles these behaviors fulfill within cetacean society, empowering us to enhance the management of their care and well-being under human stewardship, while simultaneously addressing their social requirements within well-administered facilities. Furthermore, considering the likelihood that these interactions assess social and motor competency, they contribute to our understanding of the intricate nature of cetacean behavior and the manner in which these interactions determine the hierarchical status of each individual animal.