Giraffes have a history of being underestimated as socially complex creatures that is almost as long as their necks. In fact, until 20 years ago, they were believed to have no social structure at all. Luckily for them, a new review has been published this week to set the record straight. Giraffes actually have social structures that are highly complex, on par with those of elephants, it reports.
In the last decade, there has been increasing evidence that giraffe social organization is more advanced than previously thought. Building on this, the study, published in the journal Mammal Review, collates information from 404 papers on giraffe behavior and social organization. Authors Zoe Muller and Stephen Harris used this information to set about testing two hypotheses about giraffe populations: first, that they have a complex cooperative social system, and second, that they form matrilineal societies – societies that trace ancestral descent through the maternal line.
They find that giraffes spend 30 percent of their lives in a post-reproductive state – the giraffe equivalent of post-menopause. This is comparable to other species renowned for their complex social structures and cooperative care, such as elephants and killer whales, which, respectively, spend 23 and 35 percent of their lives in this state. Muller and Harris suggest that this supports the conclusion that giraffes engage in cooperative parenting, along matrilines, collectively contributing to shared parental care of offspring.
In mammals, this is referred to as the “Grandmother hypothesis” – post-menopausal females live far beyond their reproductive years to help to raise the offspring of younger generations. This enables successive generations to have more young and thus facilitates the preservation of species.
The review also reports that giraffes exist predominantly in stable female-only groups, forming strong female-female relationships, as well as mother-calf relationships that can last for up to 15 years. This is not the first we’ve heard of behavior like this in giraffes; a previous study found that their fondness for female friendship is not only very sweet but may confer a survival advantage, helping them to live for longer. Males, on the other hand, the paper finds, tend to form weaker bonds that do not last. They also tend to roam further from where they were born than females do, and are not often involved in the raising of calves. These findings all led to the conclusion that giraffe societies are complex, cooperative, and matrilineal.
“It is baffling to me that such a large, iconic, and charismatic African species has been understudied for so long. This paper collates all the evidence to suggest that giraffes are actually a highly complex social species, with intricate and high-functioning social systems, potentially comparable to elephants, cetaceans, and chimpanzees,” Muller said in a statement.
“I hope that this study draws a line in the sand, from which point forwards, giraffes will be regarded as intelligent, group-living mammals which have evolved highly successful and complex societies, which have facilitated their survival in tough, predator-filled ecosystems.”
Appreciating the complexities of these societies is fundamental in furthering our understanding of giraffes behavioral ecology and conservation needs. Giraffe numbers have declined by 40 percent since 1985, and they have been declared extinct in several countries. The authors hope that their research may help much-needed conservation efforts to protect our long-necked pals.
“Conservation measures will be more successful if we have an accurate understanding of the species’ behavioural ecology. If we view giraffes as a highly socially complex species, this also raises their 'status' towards being a more complex and intelligent mammal that is increasingly worthy of protection,” Muller said.