The question of whether whales and dolphins experience emotions is complex, forcing a consideration of how feelings manifest in creatures with a biology vastly different from our own. To understand this, scientists look for evidence of complex internal states, often referred to as sentience—the capacity to feel, perceive, or experience subjective feelings. This concept moves beyond mere instinctual response, suggesting an animal possesses a conscious awareness of itself and its environment. Examining the physical structures of the brain and observing documented behaviors in the wild provides insight into the emotional lives of cetaceans. The evidence suggests that these marine mammals are far from simple automatons, instead demonstrating a rich capacity for complex emotional processing.
Neuroanatomy Supporting Complex Emotion
The sheer size and intricate structure of the cetacean brain offer a compelling starting point for discussing complex emotional capacity. The brains of many whales and dolphins are among the largest in the animal kingdom; for example, a sperm whale’s brain is significantly larger in absolute mass than that of an elephant. Beyond size, the brain’s outer layer, the neocortex, exhibits an extraordinary level of folding, or gyrification, that surpasses that found in all other mammals. This extensive folding increases the surface area available for neural connections, a feature commonly associated with advanced cognitive functions. The cetacean neocortex, while organized differently than the primate brain, contains large, complex regions consistent with high-level functions like attention, social awareness, and judgment.
A more specific piece of neurobiological evidence is the presence of Von Economo neurons (VENs), also known as spindle neurons. These specialized cells are large, elongated neurons found primarily in the anterior cingulate and anterior insular cortices—brain regions linked to social cognition, self-awareness, and emotional processing in humans and great apes. The distribution and size of VENs in large-brained cetaceans are remarkably comparable to those observed in hominids. This independent evolution of VENs suggests a strong selective pressure for the development of complex social and emotional capabilities. The presence of this neural hardware provides a physical basis for the elaborate social and emotional lives observed in these marine species.
Behavioral Indicators of Grief and Joy
The hypothesis of complex cetacean emotion is strongly supported by consistent observations of social behaviors that are difficult to explain through simple instinct. One of the most frequently documented emotional responses is deep mourning or grief, evidenced by “postmortem-attentive behavior” in at least 20 species of cetaceans. This involves individuals attending to a deceased companion or offspring, often for extended periods. A well-known example involved a killer whale mother who carried the body of her deceased calf for over two weeks, pushing and nuzzling the body to keep it afloat. This behavior is costly, diverting time and energy away from essential activities like foraging and mating, suggesting a powerful emotional drive rather than a simple reflexive action.
Researchers have also observed captive bottlenose dolphins displaying depressive-like behaviors, such as lying listlessly on the pool bottom, following the death of a companion. The complexity of cetacean emotion also extends to expressions of joy, strong social bonds, and altruism. Playful interspecies interactions are common, with studies documenting mutual engagement between dolphins and whales, often initiated by dolphins swimming near a whale’s head. Humpback whales sometimes respond to these approaches by rolling, exposing their bellies, or gently moving a pectoral fin, with about a quarter of interactions being classified as mutually playful.
Altruism, the act of helping others at a cost to oneself, is also frequently observed, sometimes even across species boundaries. Humpback whales have been repeatedly documented intervening to shield other marine mammals, such as seals and sunfish, from killer whale attacks. This is considered highly altruistic because the action carries significant risk and offers no direct, immediate benefit to the rescuing whale.
In one instance, a bottlenose dolphin was observed in New Zealand actively guiding two stranded pygmy whales back into deeper water after conservation officers had struggled to do so for hours. This kind of voluntary, selfless cooperation demonstrates a capacity for empathy and complex social awareness. Such behaviors go beyond instinct, reflecting an ability to recognize distress and intentionally provide aid.
Scientific Consensus on Cetacean Sentience
The cumulative evidence from neuroanatomy and behavioral observations has led to a major shift in the scientific community’s understanding of whales and dolphins. The traditional view of these animals as purely instinct-driven has been widely replaced by a recognition of their status as highly cognitive and potentially emotional beings. This modern perspective acknowledges that their sophisticated social structures and long-term bonds necessitate a complex inner life.
In 2012, the Cambridge Declaration on Consciousness formally asserted that non-human animals, including cetaceans, possess the necessary neuroanatomical, neurochemical, and neurophysiological substrates for conscious experiences. This declaration reflects a growing consensus that these species are not only conscious but are also capable of experiencing a range of emotions.
This advanced understanding has prompted international movements to grant cetaceans greater moral and legal protection. Based on their intelligence and self-awareness, many scientists and advocacy groups now argue that whales and dolphins should be considered “non-human persons,” not property. This recognition would grant them fundamental rights, such as the right to life, liberty, and freedom from harm, a position that has already been adopted by some governments, like India, which banned cetacean captivity and declared them nonhuman persons in 2013.