Giraffes are the tallest living land animals, the largest existent ruminants, and one of the most eye-catching members of African wildlife. They’re an animal that guests from all over the world are most excited to see, and we’re lucky enough to see them on the majority of our game drives. It comes as a big surprise then, that little research has plunged into the complexities of the giraffe species.
In the last 10 years, efforts have increased to understand these towering creatures, specifically regarding how their social organisation is much more advanced than we once thought.
Traditionally, giraffes have been considered to have little or no social structure, and only fleeting, weak relationships. I very much also believed this as it’s stated in most textbooks and because of the noticeable daily fluidity in their group composition.
Giraffes are said to be non-territorial and sociable, living in loose open herds. At a given moment a giraffe may be in a herd composed of all males, all females, females and young, or of both sexes and all ages – or alone if it is a mature bull or cow guarding a new calf. There are no leaders and minimal coordination of herd movements. There is very little structure to a group of giraffes.
New and exciting evidence!
I recently came across a paper published in 2021 in the Mammal Review journal by Zoe Muller. She explains that as experts have begun to pay closer attention to these lanky icons, a different social picture has begun to emerge, unlike the traditional one I mentioned earlier.
In the study, two hypotheses were tested:
Giraffes have a complex cooperative social system
This idea was exhibited by a few behaviours: First, stable groups of females stay together. Second, offspring stay in their natal group for part (males, who will move off at around three years of age) or all of their lives (females). Third, there is support by non-mothers in rearing young and lastly, there are non-reproductive females in the group.
Giraffes form matrilineal societies
Evidence for this was found by looking at male dispersal from herds, female philopatry (I will explain this in a little bit), assistance in raising or protecting offspring, and individual benefits gained from social foraging.
In this blog, I will dive a little deeper into one behaviour in each hypothesis that struck me the most. Namely, the presence of non-productive females in the herd (in the first hypothesis) and female philopatry (in the second hypothesis).
The presence of non-productive females
What do non-reproductive females have to do with anything?
Well, results showed that giraffes spend up to 30% of their lives in a post-reproductive state. This is similar to other species with complex social structures and cooperative care, such as elephants and killer whales. In these species, it has been proven that post-menopausal females offer survival benefits for related offspring.
In mammals – including humans – this is known as the ‘Grandmother hypothesis’: it proposes that females live long past menopause so that they can help raise succeeding generations of offspring, thus safeguarding the preservation of their genes.
The researchers suggest that the presence of post-reproductive adult female giraffes could also function in the same way, and supports their claim that giraffes engage in cooperative parenting, along matrilines, and add to the shared parental care of related calves.
(of an animal or species) tending to return to or remain near a particular site or area.
Along with giraffes, most female mammals show high levels of philopatry. Female home ranges are smaller than those of males and their ranging patterns indicate habituation within a defined area, even in unfenced ecosystems, whereas males exhibit dispersal and migration. As adult females establish stable groups within a specified area or home range, repeated interactions are promoted with known individuals, forming a “friendship” of sorts.
Why is it important to research animal behaviour more?
It came as quite a shock to me how little research had gone into giraffes before the last decade. Recognising that giraffes have a complex cooperative social system is important as it will broaden our understanding of their conservation needs. If we understand giraffes as a highly socially complex species, this grows their ‘status’ towards being a more intelligent mammal that is worthy of protection.