To evolve to be faster than cheetahs, there must be strong natural selection on the gazelle. That means any gazelle that cannot run faster will die and only ones that can run faster will survive and reproduce. Since predators in general are less abundant than prey, and since predators do not succeed in hunting on every occasion, and since predators do not hunt unless they are hungry, that means it is rare for such strong selective pressure to exist. Being fast has its cost. A fast animal cannot be very heavy, and it therefore must be lean. Being lean means being less powerful. The cheetah is not as powerful as a lion, leopard or hyena as a result. The cheetah loses many of its kills to stronger predators.
A weak gazelle may lose a fight with rival males for the right to reproduce. Therefore being lean and weak may be more of a disadvantage than being slow, if the typical gazelle does not get chased very often during its lifetime (because cheetahs do not hunt very often and because there are a lot of gazelles and other prey species around). As a result, it may be unnecessary and even disadvantageous for the gazelle to evolve to be faster than the cheetah.
· 1 month ago