Dolphins are intelligent marine mammals, often depicted as friendly and playful. While their social nature is well-documented, public perception often overlooks their intricate and sometimes aggressive aspects. Their behavior extends far beyond common portrayals, encompassing a range of aggressive interactions.
Common Misconceptions About Dolphins
Media portrayals, like “Flipper,” often depict dolphins as docile, smiling, and heroic. This perception suggests they are harmless companions, devoid of aggressive tendencies. Many are surprised that a dolphin’s permanent “smile” is simply the shape of its jaw, not an emotional indicator.
This belief contrasts with the reality that dolphins are wild, powerful predators with sharp teeth and complex social structures. They are not pets; interacting with them can disrupt natural behaviors. Their intelligence and social dynamics, including hierarchies, do not preclude aggressive actions.
Manifestations of Aggressive Behavior
Dolphins exhibit aggression in various ways, both within their own species (intra-species) and towards other marine life (inter-species). A common aggressive act is “raking,” where dolphins scratch one another with their teeth, leaving superficial parallel marks on the skin.
Aggressive physical displays include biting, ramming, and chasing, often seen during disputes over dominance or mating rights. Posturing, like head-to-head displays and open-mouth gestures, also asserts dominance. Other threat signals include jaw clapping, tail smacking, or emitting bubble clouds from blowholes. More severe cases involve body slamming or pinning another individual to the seafloor.
Underlying Causes of Aggression
Aggressive behavior in dolphins is driven by biological and environmental factors. Competition for mates is a significant cause, with male dolphins often engaging in fierce battles involving biting and ramming to establish dominance and secure breeding opportunities.
Dolphins also exhibit aggression when defending territory or competing for food. While territoriality over specific physical boundaries may not always be the primary driver, competition for prime hunting grounds can lead to conflict. Defense of calves, themselves, or their pod from threats, such as sharks or other dolphin groups, also triggers aggressive responses; dolphins have been observed attacking and killing sharks in the wild. Environmental stress or human interference can also contribute to aggressive displays.
Dolphin Interactions with Humans
While generally not aggressive towards humans, instances of dolphin aggression can occur, especially when habituated to human presence or feeding. Wild dolphins may lose natural wariness when frequently offered food, associating people with handouts. This habituation can result in pushy, aggressive, or threatening behavior if an expected reward is not received.
Aggression towards humans can also stem from misinterpreting human actions as threats or accidental injury during close encounters. For example, a woman who fed and swam with dolphins was bitten, requiring hospitalization. In captivity, dolphins may exhibit distorted behaviors, including aggression towards tank mates and humans, due to limited space, unnatural groupings, and chronic stress. Dolphins are powerful wild animals; maintaining a respectful distance, typically at least 50 yards (approximately 45 meters), is recommended for human safety and dolphin well-being.