Whales breaching, where these marine mammals propel themselves out of the water, is a spectacular sight. While not fully understood, scientists have developed several hypotheses to explain this energetic activity. This behavior serves multiple potential functions.
Communication and Social Signaling
Breaching serves as a powerful form of communication among whales, utilizing both visual and acoustic signals. The large splash created upon re-entry into the water generates a loud sound that can travel for miles underwater, making it an effective long-distance signal. This acoustic signal can alert other whales to their presence, especially when they are far apart or when underwater vocalizations might be obscured by ocean noise.
Beyond simple alerts, breaching conveys more nuanced messages. Whales in groups are more prone to breaching, suggesting it functions as a non-verbal signal during social interactions. It may be used for group coordination, asserting dominance, or signaling excitement. Different surface behaviors, such as full breaches, half breaches, or chin-slaps, might carry distinct meanings. The energy expended in a breach can act as an “honest signal” of a whale’s physical fitness and strength, important in social hierarchies or during mating seasons.
Physical Needs and Environmental Awareness
Breaching may also serve practical purposes related to a whale’s physical well-being and its environment. One theory suggests that the impact with the water helps dislodge external parasites, such as barnacles or whale lice, or aids in shedding dead skin. Humpback whales, for instance, are known to shed skin, and breaching can facilitate this process.
Another hypothesis is that breaching allows whales to gain a better vantage point of their surroundings. By lifting a significant portion of their body out of the water, whales can scan the horizon for navigation cues, locate prey, or identify potential predators. The powerful splash generated can also disorient or stun schools of fish, making them easier to catch, a strategy more frequently associated with tail or pectoral slaps.
Play and Display
Breaching is also a form of play or a display. Young whales frequently engage in breaching, suggesting a playful element or a way to develop motor skills and coordination. This behavior mirrors how many intelligent species engage in play to learn and socialize.
Adult whales may breach as a show of strength, particularly during courtship rituals. This display of power and agility serves as a means for males to demonstrate their fitness to potential mates. Breaching can be a form of enjoyment, allowing whales to express themselves.