1 November 2011, by Tamera Jones
If you're trying to drum up a crowd to go out for a drink after work, you're more likely to succeed if you're popular. Otherwise, you'll probably be going to the pub on your own.
Now the latest research suggests that similar rules apply to the wild chacma baboons of Namibia; it turns out that the best leaders are the most sociable types with lots of friends.
A European team of scientists found that when one baboon sets an example by moving off in search of breakfast, the others follow. But these movements are far from random. Instead, they appear to follow a clearly-defined rule; baboons that are central in the grooming network have the best chance of being followed.
In contrast, the troop is unlikely to follow less popular baboons at the periphery of the network who try to initiate a departure.
'It appears that a baboon thinks 'ok, I'm going', and strides off purposely, so the rest follow,' says Dr Andrew King from the Royal Veterinary College at the University of London, who led the study, published in Animal Behaviour.
'It's basically like an afternoon in the office: a couple of people suggest going to the pub, and no one really responds. But then someone who is very popular pipes up and declares they are going, so the whole office goes.'
King and colleagues wanted to know how groups of baboons manage to stick together when searching for food. 'When deciding where to eat, it makes sense for individual baboons to agree on where to go and then go together, otherwise they'll lose the benefits of being in a group,' he explains.
But how this is orchestrated was unclear until now. So King and his colleagues analysed the movements of the animals away from their cliff-top sleeping sites in Tsaobis Leopard Park in Namibia.
Initially the researchers thought the leaders' grunting or backward glances might have been the cue that triggers the troop to follow.
But they soon found that this wasn't the case at all. In fact, if a baboon used backward glances, he or she was less likely to be followed, reinforcing the idea that assertive baboons tend to lead.
'We expected grunting and backward glances would be important cues the baboons would use. But we didn't see this,' says King.
Grunts might not be important in Namibia, because the baboons are out in the open, so it's much easier for them to keep an eye on what their neighbours are doing. But in a forest setting, it may well be a different story.
The researchers then wondered if age, sex or dominance rank might predict how good a leader a baboon would be. But they found no effect at all. Yet the alpha male did tend to be more successful than average at initiating foraging trips.
'It might be that the alpha male ends up leading the troop in the mornings, but this is not because he is more dominant, or aggressive, it is because he has more friends,' says King. 'He defends the troop against threats, and secures the best food patches, so it's worth grooming him, and investing in a relationship with him.'
There are many benefits to following friends in complex social societies. Previous studies have revealed that the most sociable females tend to have offspring that survive for longer. While other studies have shown that breastfeeding females seek the company of males to protect their babies from attacks.
'Social relationships are really important. Research by colleagues working with baboons in Kenya and Botswana has shown that female baboons who get on best with others tend to have more babies, and these babies are more likely to get to adulthood and have young of their own,' King says.
'We're now keen to find out if personality predicts whether or not baboons will be leaders,' he adds.