Why don animals migrate like birds?
They do. I assume by animals you mean non-flying animals, because birds are a subset of the animal kingdom. Many land-based animals migrate, especially if they are in areas that experience great seasonal changes (flooding, extreme heat/cold) or if they live in areas with scanty resources (desert, tundra.) Their ranges tend to be smaller because they don’t have the mobility their airborne cousins do. Also, sea animals such as whales migrate.