Giraffes seem to stand above everything. Like two-story ascetics, they float over the savannah and peer out at the turmoil behind their long eyelashes. For decades, many biologists thought that giraffes extended this treatment to their fellows as well.
But lately, when experts paid more attention to these lanky icons, a different social picture has emerged. Female giraffes today are known to enjoy years of bondage. They eat pals, guard dead calves, and stay with their mothers and grandmothers. Women even set up common day care centers, so-called crèches, in which they take turns babysitting and feeding their boys.
Observations like this have reached critical mass, said Zoe Muller, a wildlife biologist who completed her Ph.D. at the University of Bristol in England. She and Stephen Harris, also based in Bristol, recently reviewed hundreds of giraffe studies to look for wider patterns. Her analysis, published Tuesday in the journal Mammalia, suggests that giraffes are not loners, but rather socially complex creatures, similar to elephants or chimpanzees. They’re just a little more subtle.
Dr. Muller’s sense of giraffes as secret celebrities began in 2005 when she was doing research on her master’s thesis in Laikipia, Kenya. There, to collect data on antelopes, she was drawn to the lanky ungulates. “You’re so funny to look at,” she said. “If someone described them to you, you wouldn’t believe that they really exist.”
After noticing that the same giraffes had a tendency to hang out – they looked like “dependent teenagers,” she said – Dr. Muller to find out about their lifestyle. “I was really surprised to see that all of the science books said they were totally unsociable,” she said. “I thought, ‘Well, wait. I don’t see that at all. ‘”
In an ecosystem full of trumpeting elephant matriarchs and fast-paced cooperative lion hunts, it makes sense that the complexities of giraffe sociality were harder to see, said Kim VanderWaal, associate professor at the University of Minnesota who also studied it. Giraffes do not communicate in ways that are obvious to us and lead quiet social lives that involve visibly obnoxious behaviors such as grooming or cooperative territorial defense. The use of digital cameras to help track people using point patterns and analysis of social networks that can reveal hidden associative patterns have made it easier to see their relationships.
The giraffe society appears to be built on strong couple bonds, especially between mothers and their cubs who grow together into kinship groups, said Dr. Muller. For Dr. Muller home, “How strong the attachments can be within a group,” she said.
But it was difficult to change her aloof reputation, she said.
For this latest paper, she and Dr. Harris reviewed over 400 studies and compiled all of the evidence. The result is “a solid scientific review” and supports the idea that “giraffe societies are far more complex than most biologists think,” said Fred Bercovitch, a conservation scientist at the Anne Innis Dagg Foundation, who does not study.
It also highlights a number of opportunities for further research. Reading through the studies, Dr. Muller that female giraffes tend to live long past their childbearing years. In other socially complex animals, including humans and killer whales, post-reproductive individuals help younger generations thrive through wisdom and care.
This phenomenon, known as the grandmother hypothesis, should be tested on giraffes, said Dr. Muller. If true, it would have conservation implications as older giraffes are often killed or trophies hunted. It would also provide more evidence that giraffes experience sophisticated forms of community. The existence of these calf nurseries could even qualify giraffes as cooperative breeders, like beavers or bush jays, said Dr. Muller.
Others are more careful. “The social structure of giraffes is complex,” and researchers are only just beginning to understand it, said Dr. VanderWaal, who was also not involved in the study. “I think more research is needed before we can conclude that giraffes live in cooperatives.”
But everyone agrees that we should keep stretching our necks until we have a better view. Giraffes are “one of the most recognizable animals in the world,” said Dr. Muller. “And we’re just starting to scratch the surface.”