Ideally, when ungulates migrate, they synchronize their movements to forage for vegetation when it's most nutritious and easiest to digest - a process called " green-wave surfing" .
But for ungulates, such as deer, sheep, and moose, it's long been hypothesized that seasonal migration is a learned behavior, passed down from one generation to the next.
In South Africa the competition for browsing on the higher branches of the acacias and other trees must be between giraffe and giraffe, and not with the other ungulate animals.