Thus, taking a longer-term perspective on inflation, central banks might be compelled to act on the build-up of financial imbalances despite having a single objective. Let us again consider the mixed herds of zebra and wildebeest in Africa. Their selection of different grass heights may account for the lack of food competition, but it cannot explain their intermingling.
However, both species face common predators, especially lions. In this context, evidence suggests that zebra benefit from the presence of wildebeest: they spend considerably less time keeping watch for predators in a mixed herd than in a zebra-only herd of the same size.