While the human concept of kindness suggests a moral motivation, ethologists examine similar behavior through the lenses of altruism, cooperation, and empathy. These pro-social actions are scientifically defined by their effect on an individual’s fitness. Many instances of animals helping others initially appear selfless, but closer examination often reveals evolutionary drivers that ultimately benefit the actor’s genes. This exploration investigates the biological evidence for social and emotional bonds in nature.
Defining Altruism and Empathy in the Animal Kingdom
In biology, altruism is defined as a behavior that increases the fitness of another individual while decreasing the fitness of the actor. This means the helping animal incurs some cost, such as expending energy or risking injury, for another organism’s benefit. Such actions are typically explained by two primary evolutionary mechanisms that ensure the actor’s genes are still passed on.
Kin selection dictates that an animal will preferentially direct altruistic acts toward its relatives. Even if the individual dies, the shared genes are preserved and propagated through the survival of its kin. Reciprocal altruism is the other main driver, where an organism helps an unrelated individual expecting the favor will be returned later. This mechanism requires individuals to recognize each other and interact repeatedly, allowing for delayed repayment.
Empathy refers to the ability to understand and share the feelings of another individual, suggesting a complex emotional state. While altruism is defined by its observable consequence on fitness, empathy is a potential internal motivation for the behavior. Identifying true empathy is challenging in non-human species, but certain rescue and consoling behaviors suggest a capacity to recognize and respond to the distress of others.
Cooperation and Shared Resources Among Group Members
Intraspecies cooperation is widespread, with many social animals engaging in behaviors that ensure the survival of the entire group. This collective action often involves sharing resources or assuming risky duties to protect the pack or colony. The African wild dog (Lycaon pictus) provides a strong example, as the pack collectively raises the pups, which are typically sired by only the dominant pair.
Subordinate members participate actively in rearing the young, regurgitating meat to feed the dominant female and the pups once they ingest solids. This intense communal care is crucial for the species’ survival, as a larger pack size is positively correlated with hunting success and overall pup survival. The helpers contribute to the group’s continued existence.
Another example of cooperative behavior is the sentinel duty performed by meerkats (Suricata suricatta) in the Kalahari Desert. One meerkat climbs to an elevated post, such as a mound or shrub, and scans the horizon for predators while the rest of the group forages. The guard emits a continuous, low-pitched “watchman’s song” to signal safety, allowing others to focus on finding food.
This sentry position is risky because the guard is exposed and may attract the predator’s attention first. However, the individual is often one who has already eaten, minimizing the cost of lost foraging time. Similarly, Belding’s ground squirrels (Urocitellus beldingi) emit loud alarm calls when a predator approaches, a behavior that puts the caller at a higher risk of detection. This action illustrates kin selection, as the alarm primarily benefits nearby relatives.
Unexpected Altruism Across Species Lines
Some of the most surprising examples of animal kindness occur between different species, transcending the immediate evolutionary logic of kin selection or reciprocal benefit. Humpback whales (Megaptera novaeangliae) have been documented intervening in attacks by killer whales, often protecting seals, ocean sunfish, and other cetaceans. In one instance, a humpback reportedly used its massive body to shield a small Weddell seal from a killer whale pod, even nudging the seal onto its chest for safety.
Dolphins, particularly bottlenose dolphins (Tursiops truncatus), have numerous documented cases of protective intervention involving humans. Off the coast of New Zealand in 2004, a pod of dolphins encircled a group of swimmers to form a protective barrier when a great white shark approached. These cetaceans have also been reported pushing drowning humans or other distressed marine mammals toward the surface, mirroring how they support injured members of their own pod.
In terrestrial mammals, cross-species nurturing is sometimes observed, often when an animal has recently lost its own young. A well-known case involved a lioness in Kenya’s Samburu National Reserve that protected a young oryx calf for several days, shielding it from other predators and her own pride. While some suggest the lioness may have been experiencing a hormonal surge, the behavior was a clear act of protective, non-predatory care for a traditional prey animal.
Other instances of interspecies bonding involve primates, which have been observed adopting and caring for young animals of other species. For example, a monkey was seen repeatedly carrying and grooming a small kitten, treating it with the same maternal care it would show its own infant. These behaviors provide compelling evidence for non-genetic drivers of pro-social behavior.
Complex Emotional Support and Mourning
Beyond simple cooperation, certain highly social, large-brained species exhibit behaviors suggesting a complex emotional response to injury, distress, or death. Elephants are the most frequently cited example, demonstrating distinct reactions to the remains of their own kind. They often approach the bones or carcasses of a deceased elephant, gently touching and examining them with their trunks, a behavior they rarely perform with the remains of other animals.
In one documented event, following the collapse of a dying matriarch named Eleanor, a female from a different family, Grace, attempted to lift and support her with her trunk. Grace remained agitated and refused to leave Eleanor’s side even after she had died, suggesting profound emotional distress. Elephants have also been observed standing vigil over a dead companion for days, and some reports describe them attempting to bury their young with branches and dirt.
Cetaceans also show signs of emotional support and mourning, especially in response to the death of a calf. Female dolphins and whales have been repeatedly observed carrying their dead young on their backs or pushing them through the water for days or weeks. This persistent behavior, despite the physical cost, is interpreted by many ethologists as a form of grief or intense attachment. The prolonged attention to the deceased indicates a level of emotional complexity that extends beyond typical survival instincts.