What dynamics move the Amboseli elephant herds?

Wed Feb 05, 2014 5:35 pm

What dynamics move the Amboseli elephant herds?

By: Vicki Fishlock, Resident Scientist, Amboseli Elephant Research Project
Posted: Tue, 02/04/2014

Amboseli is fresh, green and vibrant in the New Year, and the elephants are travelling together in big groups, creating a spectacular sight for visitors…and some serious work for elephant researchers.

Why do elephants “hang out” the way they do? And what behavioural insight can we glean from the dynamics of these enormous throngs of pachyderms?

Even with a whole ecosystem to range over (Amboseli elephants are the lucky ones), what fascinates me as a researcher are the choices they make on where to go.

Searching for my focal families in the groups of two or three hundred elephants is time-consuming, sometimes taking me an hour or more. It’s best to get out to them early, giving me time to find the family I am looking for before the group starts travelling. There is no predicting when they might decide to get underway that morning. The best days are when the elephants aren’t in any hurry, sometimes only making it to the central swamps at noon.

I have to wonder a bit why they go to the swamps at all, given that there is fresh lush grass to be had all around (which is much more nutritious than the swamp plants) and enough standing water for them to enjoy a cooling mud splash.

I definitely know there is water because I have narrowly avoided plonking the Land Rover in one of the deep depressions the elephants like to use on several occasions. These holes are generally hidden in the lee of bushes or taller grass, but luckily my “shimo radar” (shimo is Swahili for hole) has let me avoid disaster thus far.

We know that while the elephants use such water for cooling off, they are picky about the water they drink, preferring the clear springs at the swamp. Females especially have to drink every day to maintain their milk production.

None of this, however, explains why families and independent males join together in groups of several hundred.

The “boring science” part of the explanation is that the fresh flush of growth means many females come into oestrus at this time of the year, attracting large musth bulls and a host of what I like to call the “ever hopefuls” – young males not nearly large enough to have a chance, but nonetheless unable to stay away from the excitement. The big bulls are attractive to other females and males alike, so the groups keep drawing in more individuals.

But it’s more than just reproduction.

Amboseli elephants have so much energy from the good growth that they have free time to socialise and play with each other, rather than just concentrating on feeding their huge bodies. (This isn’t to say they’re not still shovelling in the greens, and one rather aromatic side effect of this sumptuous diet is some rather runny elephant tummies.)

This time spent in big groups is important for reinforcing friendships, and for learning about what is going on in other families. Young elephants find new playmates, and males begin to establish friendships and dominance hierarchies that will play out over the rest of their lives.

Elephants learn from each other constantly, and carefully watch the interactions between others: young females in their first oestrus may be actively taught correct behaviour by older females.

Sometimes all this social interaction spills over into a play frenzy, where adults and calves alike will rush about with exaggerated postures, thrashing vegetation and vocalising.

Alternatively, the excitement may get too much and in a classic “tears before bedtime” scenario, boisterous behaviour is censured by one of the big females, often chasing away a playmate from another family.

Collecting systematic scientific data in these circumstances is not easy. With smaller groups of elephants, we collect a lot of very detailed information: who is next to whom, all the touches and exchanges between individuals. All these interactions build up into patterns of relationships.

In these big groups however, there is a lot going on, and the sea of bodies closest to the car usually hides most of the view. Even getting a good count and identifying which families and bulls are present takes a long time, let alone checking that all the family members are present.

I often make a map so that I can later record which families were where: which family was leading, which was at the side and heading off in a different direction.

Within families, matriarchs often “lead from the rear” providing a safe rallying point when threats are encountered.

We are trying to understand more about which elephants drive the movements in these big aggregations, as well as where and how families travel in a stop-start fashion, feeding along the way.

Getting into big groups serves many important social and reproductive functions for the elephants, but more than anything I think their main reason for doing it is that they enjoy the fun and chaos that ensues.

Those cheeky elephants…