The concept of a caste system brought me back to Wynona and the poorly attended birth of her new baby. With so much aggression toward low-ranking little ones, perhaps Wynona put some distance between herself and extended family members to protect her baby from their hostile behavior.
Researchers often describe female elephants as living in “fission-fusion” societies. But the implication is that the fission dynamic—the forces pulling the groups apart—is passive, that somehow the optimal number of elephants that forage and survive together is achieved when extended families slowly develop looser connections and become more distantly associated.
I was now starting to realize that the dynamic might be active, possibly following the direct bloodline of the matriarch, where only the highest-ranking, or “queen,” elephant and her direct descendants are welcome to hold court around the best water. Others are pushed away, forced to splinter off into separate groups.
There had to be an explanation for such targeted aggression toward family members. In other areas of Africa, where poaching is more prevalent, unrelated females have joined together to form new groups. Hostilities in those makeshift families might make sense, but elephants at Mushara are not under the same kind of pressure. What’s more, according to our records, both Paula and Wynona had been living within their families for at least the past eight years. And while it’s conceivable that a whole family might ostracize a sick elephant, chances were low that Paula, Wynona, Greta and their calves were all ill.
It struck me how much energy the higher-ranking females devoted to keeping the heat on the lower-ranking ones, not to mention the coordination involved. Mia trunk-slapped Paula again and again and again.
Perhaps the concepts of optimal foraging and survival of the fittest were at work here—that group sizes had to be maintained at a number that optimized the foraging opportunities of higher-ranking females and their calves in order to ensure the survival of the next generation. The chances that a calf would survive would increase with group size to a point. But a larger group at some point could become a hindrance, making it harder to find enough food, particularly in dry years.
As for Paula, Wynona and Greta, the matriarchs of their families might be ostracizing them in an effort to preserve the reproductive success of the higher-ranking and perhaps more closely related individuals—even if it takes energy in the short term to consistently antagonize subordinates and their offspring. Alternatively, this concerted effort might exist to minimize or prevent reproduction in lower-ranking females.
By collecting fecal DNA from as many individuals and family groups as possible, I hoped to piece together an extended family tree that would either support my hypothesis or further complicate the picture. But that would take time, at least an additional year to finish the data collection and analysis needed. All I had in front of me was the behavior, and I did my best to document it. I reported a number of my observations in a blog I wrote last year for the New York Times, but only later did I formulate the evidence I’d accumulated into this hypothesis: Hierarchy is hereditary and it is the driver of an active, not passive, fissioning process.
As the season wound down at the beginning of August, the wind started to pick up. The dust of Etosha Pan blanketed the sky as twisters funneled their way across the clearing. The elephants were slower in coming to the water hole, the environment interfering with the smells and sounds that help them navigate.
The relative calm gave me time to assess Paula’s situation, which was clearly taking its toll on her and her calf, Bruce. She was with the Athletes a few days ago looking stressed. And Bruce hadn’t yet gained sure footing. On that occasion, the whole family came barreling in as usual, but this time headed straight for the pan for a cooling bath before going to drink from the trough.