Playful mouth-to-mouth interactions of belugas (Delphinapterus leucas) in managed care.

Belugas (Delphinapterus leucas) engage in many forms of play (e.g., object, water, locomotor), but no play is quite as curious as the unusual form of cooperative social play involving mouth-to-mouth interactions. These playful interactions are characterized by two belugas approaching each other head-to-head and interlocking their jaws, clasping one another, as if they were shaking hands. Observed in belugas both in the wild and in managed care, it is seemingly an important type of social play that offers a unique way of socializing with conspecifics. To describe this unusual behavior, a group of belugas in managed care was observed from 2007 to 2019. Although adults participated in mouth-to-mouth interactions, most were initiated and received by young belugas. Both males and females engaged in mouth-to-mouth interactions and did so at similar frequencies. Individual differences in how many mouth-to-mouth interactions were initiated among calves were also observed. Due to the unique, cooperative nature of mouth-to-mouth interactions, which require both social and motor skills, it is hypothesized that these interactions may be used to test social and motor competency.