TROOPING THE NUMBERS UMBERS
Baboons troops can contain anything from a handful to hundreds of individuals. But University of Oxford biologists have discovered that some group sizes are more common than others and, what’s more, that there’s an intriguing mathematical relationship between them – 20, 40, 80 and 160.
Part of the reason is that baboon troops divide in two once they reach an upper threshold. That’s because, as social complexity increases, females produce offspring at a slower rate. The result is that any given troop oscillates between a high and low populationn size – 20 and 40, 40 and 80 or 80 and 160.
Which pair of sizes a troop oscillates between seems to depend onn the local risk posed by predators.ors. Larger groups are better at defending themselveses against the likes of leopardsopards and lions. So, inn regions where the density of predators is high and there is littletle shelter, it pays to oscillate between a higher pair of troop sizes. zes.
Baboon troop numbers tend to follow a sequence.