When confronted by a predator, some members of the red deer species produce a barking sound to alert the rest of the herd and make good their escape. Ground nesting birds like the killdeer draw predators away from their nesting sites by pretending to be debilitated, so they can protect their offspring.Dolphins support injured animals by swimming under them and pushing them to the surface so they can breathe.What they all have in common is that they’re helping others with no regard for their own safety or benefit. This is the puzzling phenomenon called altruism.
Altruism disturbs the fundamental tenets of Charles Darwin’s theory of natural selection. In fact, in his book The Descent of Man (1871), Darwin wrote, “He who was ready to sacrifice his life, as many a savage has been, rather than betray his comrades, would often leave no offspring to inherit his noble nature.” So in this world of ‘dog eat dog’, altruism seems out of place, an ideal for social structures while also seeming impossible to realise. This paradox inhabits the nature of altruism.
In the wasp species Ropalidia marginata, the queen has the ability to reproduce while the workers are sterile. So natural selection would suggest that the workers would have a lower survival rate. This isn’t the case: many individuals help queen wasps raise and produce more offspring.Similar behaviour has been observed in honeybees as well. Is this selfless behaviour? Not exactly – but it has implications for the scope of Darwin’s ideas.
In an effort to explain such behaviour, the renowned English biologist William Donald Hamilton had posited the idea of ‘kin selection’, which in turn hinged on inclusive fitness as opposed to Darwin’s notion of personal fitness. Hamilton suggested apart from making oneself fitter, natural selection also acted to increase the representation of one’s alleles genes by promoting the survival of one’s genetic relatives.
This explanation implied a connection between the odds of an individual being altruistic and their closeness with the individual they’re helping. In other words, an individual was likelier to be altruistic if they were helping out a closer genetic relative.
The American biologist Edward O. Wilson proposed in 2000 that this social behaviour was genetically determined – i.e. that it was encoded in the genes – although this claim remains shrouded in controversy, especially since he withdrew his statement in 2010 after insufficient evidence was found for it. At the same time, the idea of ‘kin selection’ versus the genetic basis of social behaviour has become one of the most hotly contested debates in evolutionary biology.
There is another model to explain altruism called the multilevel selection model, based on group-level selection. Here, different levels of individuals and groups function in a close-knit manner to promote and maximise fitness, or reproductive success.
The competition between these theories shouldn’t take away from the wonder inherent to various aspects of altruistic behaviour.
For example, the parental instinct is closely associated with our idea of selfless behaviour. Many species make boundless sacrifices for their offspring, some even risking their own lives. The females of the octopus species Graneledone boreopacificaguard their eggs till they hatch – a period of three months in a deep sea environment and the mothers often die due to exhaustion.
Sometimes, however, selflessness also comes with a rider. For example, this is observed when male baboons form coalitions to overcome a higher-ranking male to gain access to a female. Such ‘reciprocal’ altruism has also been observed in vampire bats, which regurgitate blood to feed members of their brood who haven’t been able to find food. This act is expected to be returned in kind by the beneficiary, and so seems more like a symbiotic relationship.
Nonetheless, completely altruistic acts have also been observed, in which the benefactor does not gain anything in return. In one study, chimpanzees chose to help members of their own species as well as those of other species, including humans. While the Dutch primatologist Frans de Waal found that chimpanzees bred in captivity do show greater altruistic behaviour than their wilder counterparts, there are examples of interspecies altruism in the wild as well.
In one heart-warming instance, a pod of sperm whales were found to have ‘adopted’ a deformed adult bottlenose dolphin. This was quite uncharacteristic for what is usually a reticent whale species.
So while there are many instances of entirely magnanimous acts, there are also numerous examples of apparent altruism with ulterior motives.
This means multiple questions remain unanswered: Is our kindness just a façade for propagating and fulfilling our own needs? Does Alexander Dumas’s “all for one and one for all” actually apply in real life, or is it simply a controlled free-for-all frenzy? More fundamentally, does true altruism exist or are we all born with an inherent selfishness? Debates centred on these ideas have no end in sight, and boast participants ranging from evolutionary biologists to psychologists.
Anoushka Dasgupta is pursuing her master’s degree in biotechnology at the Institute of Bioinformatics & Biotechnology, Savitribhai Phule Pune University. She is interested in science writing.