Beluga whales are fascinating marine mammals, known for their distinctive white coloration and unique vocalizations, earning them the nickname “sea canaries.” These highly social creatures exhibit a range of intriguing behaviors, among which the opening of their mouths often captures attention. While this action might appear simple, it serves a variety of complex purposes depending on the specific situation. Understanding why belugas open their mouths reveals insights into their communication, feeding, and interaction with their environment.
Communicative Expressions
Beluga whales frequently use mouth opening as a form of non-vocal communication within their social structures. This behavior is a visual signal that complements their extensive acoustic repertoire, including whistles, clicks, and chirps. An open mouth can convey various messages, ranging from expressions of dominance and submission to indications of playfulness or warning.
Context clarifies the meaning of an open mouth display. In certain situations, particularly in managed care environments, an open mouth can signify aggression or a threat. However, it also plays a role in socio-sexual interactions, establishing social hierarchies, demonstrating interest, or testing boundaries. Belugas can visibly alter their melon, a fatty organ on their forehead, and open mouth displays can modulate these visual signals, suggesting sophisticated nonverbal communication. This behavior is also observed during playful interactions, such as mouth-to-mouth contact, a significant social play behavior, particularly among younger belugas.
Foraging and Feeding Techniques
Beluga whales use their mouths extensively for feeding, employing specialized strategies. Their primary method of capturing prey is suction feeding, where they open their mouths wide to create a vacuum, drawing in fish, crustaceans, and other marine organisms. This technique is particularly effective for their diet, including smaller prey items.
Unlike many other marine predators, belugas do not use their teeth for chewing; instead, their small, blunt teeth are for grasping or holding prey before swallowing it whole. Their highly flexible lips and tongue allow them to form a tight seal around prey and manipulate food before ingestion, preventing water from entering their respiratory system. Belugas can also expel strong jets of water from their mouths to uncover benthic prey, such as invertebrates hidden in sand or silt on the seafloor. While they often hunt alone, belugas sometimes cooperate in groups to herd schools of fish into shallow waters, where they can more easily capture them.
Sensory Exploration and Environmental Interaction
Belugas use their mouths as a sensitive tool to explore their surroundings. Their lips and mouths are highly tactile, extending their sensory system, which is especially beneficial in the murky, often low-light conditions of their Arctic and sub-Arctic habitats where vision may be limited. This allows them to investigate unfamiliar objects by “tasting” or “feeling” them for information on composition and texture.
This sensory exploration is distinct from feeding, as no ingestion occurs. Belugas may prod and interact with habitat elements like ice formations or rocks, using their sensitive oral structures. Additionally, belugas have been observed using water-spitting to interact with their environment, sometimes even in a tool-like manner during play. This behavior highlights the dexterity and adaptability of their mouths beyond communication or foraging.