Does it pay for animals to act altruistically? One species with a particularly strong community-spirit is the meerkat. To find out more about why meerkats help each other out, rather than just fend for themselves, Lewis Thomson and Katie Haylor met up with one human expert, and many excitable meerkats...
Tim - Hello, I’m Tim Clutton-Brock. I’m a zoologist at the University of Cambridge and I work principally on Kalahari Meerkats and we work in a site in the southern Kalahari just on the South African-Botswana border.
Lewis - We’re not in the Kalahari right now. We have come to the Animal Experience in Cambridgeshire and we’re surrounded by about five meerkats I think. They’re all running around. Shall we go in and sit down and get a bit closer to them?
Tim - Fine.
Lewis - They’re climbing over Tim’s shoe at the moment. I’m not sure if he thinks it’s food. No… don’t go for the microphone cable.
Tim - I’ve got a meerkat on me.
Lewis - He wants to be interviewed.
Tim - He wants to smell my mouth too closely I think. The unusual thing about meerkats is that they’re one of the most cooperative animals in the world and for evolutionary biologists cooperation poses a problem. It’s not difficult to understand why animals compete with each other because they’re competing for food and breeding opportunities and so on. But meerkats, like a number of social insects, spend much of their time helping other individuals to breed rather than breeding themselves.
Groups typically consist of one breeding male and one breeding female, and then a variable number of individuals, sometimes 20 or 30 individuals, many of them fully mature who spend a large part of their lives helping to rear offspring born to the breeding female. They enjoy eating people’s ears…
Tim - Eventually the meerkats decided that our producer’s ears weren’t really worth eating. Back to Tim…
Tim - Cooperation on this level is unusual in mammals. Meerkats have a complex system of helping so that when the dominant female is producing pups, other individuals clear out the burrow, and some of the non-breeding females will lactate to the young of the breeding female. When the group leaves the breeding burrow in the morning to go foraging and the breeding female goes with them, one of the helpers will stay and protect the young for the rest of the day with a result that they will spend a full 24 hours without getting any food.
Then once the pups start to move with the group and forage, which they do at about three weeks after they’re born, the members of the group go and collect food and they bring it to the pups. Most of the members of the group give away around half of all the food they find to the pups and they do that for the first three to four months of pup life. When the groups foraging, it’s commonly the case that one individual stops feeding, goes up on raised guard and looks for predators, and gives alarm calls if it sees predators.
Lewis - This raised guard is that classic image of meerkats standing up like footballers defending a free kick. They’re ready to alert their troup to any eagles, snakes, or jackals… So why put their neck on the line like this?
Tim - The only animals that live in cooperative systems like this are animals where all the group members are closely related because most of them in a meerkat group, most of the individuals are full siblings. So they’re helping to rear individuals that are 50% related to them which is the same level of relatedness as their offspring would be if they produced offspring themselves. If their parents are much more likely to be able to produce and rear offspring than they would themselves, another way of breeding, if you like, is to help their parents produce further siblings rather than trying to breed themselves.
Lewis - But why does being closely related, that is having a similar genetic makeup or genotype matter?
Tim - Well, if you put it in the simplest way, animals are selected to maximise the proliferation of their genotype in future generations. So, if you’re helping to rear individuals that are 50% related to you, you’re extending the proliferation of your genotype into future generations just as you are if you breed yourself. If, on the other hand, you’re helping an individual that’s only 5% related to you, you are making very little contribution by that to the proliferation of your genes into future generations.
Lewis - Do you think altruism is an appropriate term to use when we’re talking about meerkat behaviour?
Tim - Well, it all depends what you mean by altruism. These individuals are helping other individuals breed, but that for them is the best way of ensuring the proliferation of their genotype. So there’s a real evolutionary benefit to these individuals, but they certainly are helping other individuals at some cost to themselves so, in the technical sense yes, I call that altruism.