22-05-2025
Three ground-breaking studies on family lives of great apes... our nearest and dearest
Homo homini lupus est — man is a wolf to man
Diogenes, 'the Cynic', rejected convention and lived in a barrel. According to historian Frederic Copleston, he did in public "what it is generally considered should be done in private — and even what should not be done in private".
'Cynic' means 'canine'; Diogenes and his followers, 'the disciples of the dog', held up the lives of animals as a model to mankind. Theirs was a moral exhortation, but studying the ways of other creatures can tell us much about ourselves.
Aristotle wrote about animals, as Pliny the Elder would do four centuries later. Porphyry, famously, advocated vegetarianism: "When animals are sacrificed, harm is done to them, in that they are deprived of soul," he declared. Caligula's alleged appointment of his horse to the Senate appears, however, to have been fake news.
Over the next two millennia, animals would be regarded as 'lesser folk', mere 'brute beasts', entirely unrelated to humans. 'I am no kin to the monkey and the monkey is no kin to me' a fundamentalist hymn proclaims. But the insights of Lamarck and Darwin would change that. They made us realise that the ways of animals are often remarkably similar to ours.
Indeed, animal studies have helped us understand many of the peculiarities of human behaviour.
Three ground-breaking papers, just published, concern the family lives of great apes... creatures which we now accept as our nearest and dearest.
Researchers from the Max Planck Institute of Animal Behaviour, working at the Tai National Park in the Ivory Coast, spent almost 4,000 hours observing 50 chimpanzee mothers with infants under the age of 10. They found that 'attachment theory', developed by psychologists studying human behaviour, can be applied to chimps.
Body contact between mothers and infants was one of the maternal behaviors examined in the study. Picture: Caroline Schuppli
'Attachment', the affectionate bond between a human mother and her offspring, is crucial to a youngster's subsequent mental and physical well-being. "Secure attachment arises from confidence in the caregiver's ability, nurtured by their high responsiveness." Faced with a strange situation, an infant will immediately seek the protection of its mother. But, if she is unresponsive, the child may exhibit 'disorganised attachment', characterised by aggressive or antisocial behaviour. Young chimps, the researchers found, exhibit 'organised' attachment, but they never show the 'disorganised' form.
The black boxes show human attachment types. The white boxes depict the respective predicted behaviour of offspring towards mothers, given the applied assessments
Another team of researchers from the Max Planck Institute have been investigating the behaviour of orang-utan females with babies in the wild. Analysing 15 year of data, they found that, just like their human counterparts, orang-utan mothers have varied and flexible approaches to caring for their infants. They "showed variation in behavioural plasticity … otherwise called maternal personality". "Mothers differed in how they modified their behaviour in response to their offspring's increasing age." They adapt their approaches as a baby develops and as circumstances change. Each mother has her own set of procedures which she uses consistently, "strengthening the notion that there is personality, specifically maternal personality, in non-human primates".
'Layered complexity', the repetition of phrases denoting particular entities, was thought to be a feature unique to human language. Now, researchers from the University of Warwick have identified similar structures in the vocalisations of orang-utans in Sumatra. This suggests that this complex linguistic trait first evolved in a common ancestor of both orang-utans and humans.
