Giraffes May Be Much More Socially Complex Than Imagined

The tallest of all land animals, the towering giraffe has been socially underestimated by researchers, a new study finds.

Long believed to have little social structure, giraffes actually are socially complex, University of Bristol scientists suggest. Their social organization is elaborate and comparable to elephants, chimpanzees, and cetaceans such as dolphins and whales.

Lead author Zoe Muller, of the University of Bristol’s School of Biological Sciences, started research work on giraffes in 2005.

“I had been doing some reading about wildlife populations, and had noticed that giraffe population numbers were declining, but yet the conservation world did not seem to recognise this, or be talking about it,” Muller tells Treehugger.

“I realised that this incredible creature had had hardly any scientific work done on it, which I just found unbelievable. I decided to dedicate my career to understanding this species better, and to highlighting their conservation plight to the public.” 

Muller and her team were building off pioneering work done in the 1950s, ‘60s, and ‘70s by biologists working to understand giraffe behavior and ecology. Then, she says, researchers felt that giraffes were considered very “aloof” and formed no long-lasting relationships.

“However, when I was working in Africa in 2005, this was not what I was seeing, and I started to question why they were described as having ‘little or no social structure’ when I could clearly observe animals that would consistently be seen together,” Muller says.

“Because the work done in the ‘50s-’70s was so comprehensive, I think scientists thought there was nothing else interesting to find out about giraffes, so they were never really studied again, until the early 2000s.”

The Grandmother Hypothesis

Muller was based in Kenya for five years, conducting research on giraffe herds and their social organization. For this latest work, she reviewed 404 papers about giraffe behavior to complete a meta-analysis. The results were published in the journal Mammal Review.

She and her team found that giraffes demonstrate many features of cooperative societies and of animals that live in a matriarchy.

“That is, giraffes may take part in shared parenting of offspring, and remain in groups of related females. These types of social organisation are well-known in other species of social mammal, for example, elephants, killer whales and primates, but nobody has ever before suggested that the same could be true for giraffes,” Muller says.

“My work suggests that giraffes are actually a highly complex, social species, that may live in matriarchal social systems and include cooperative care of young.”

The researchers estimate that giraffes spend almost a third of their lives in a post-reproductive state when they are no longer able to reproduce. These animals live past menopause so they can help take care of related offspring. In mammals (including humans), this is known as the “grandmother hypothesis.”

“The grandmother hypothesis essentially identifies that older adult females (‘grandmothers’) that stay in their family groups after they can no longer bear offspring, pass on survival benefits to the younger members of the group,” Muller explains.

“These ‘grandmothers’ contribute to the group by offering shared care of young, but also are a repository of knowledge, which can offer the group survival benefits in tough times, for example, they may know where there is water during a drought, or where they can find food during times of famine.”

Giraffes in the study group spent up to 30% of their lives in this state, compared to 23% for elephants and 35% for killer whales. Those are both species with very complex social structures and cooperative care.

Next Steps

Muller has suggested key areas for future research in order for scientists to recognize giraffes as a socially complex species.

“Recognizing that giraffes have a complex cooperative social system and live in matrilineal societies will further our understanding of their behavioral ecology and conservation needs … 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 says.

She suggests a better understanding of the role that older, post-reproductive adults play in society and what fitness benefits that offer for the group’s overall survival.

Her research not only identifies that giraffes are a much more socially complex animal than scientists previously thought, it also theorizes that the presence of older females may contribute to a group’s survival.

“This is critical information, as this means we should focus on preserving the older adult females in order to support conservation work,” Muller says. “In southern Africa, it is common practice to cull or hunt older individuals, but if these individuals are important repositories of knowledge to aid survival of younger generations, then this has as-yet-unidentified consequences.”