Inactive Tutor answered • 23d
Well, there are a few things to consider here.
First, in the evolutionary arms race the cheetahs are also always changing too. If the prey can get faster, then the predators will also get faster. This is what is called the red queen hypothesis, where both animals are constantly adapting in order to stay in the exact same place relative to eachother. Alternately, cheetahs could develop a whole other mutation that still lets them catch the prey regardless of how fast they run. Maybe the cheetahs will develop better camouflage, since running speed won't matter if you catch your prey by surprise. Another fun option would be cheetahs developing endurance hunting, it doesn't matter how fast your prey can run if you can keep running long after your prey has exhausted itself.
Second, when it comes to life history strategies everything comes with trade offs. There is no such thing as a master body plan that can do everything perfectly, being good at one thing usually makes you much worse at something else. Because species have to overcome many challenges to survive, investing so many resources towards a single issue makes our prey animal vulnerable to others. Maybe the speed focused body plan is less resilient to extreme climate conditions, so the speediest individuals die off during a particularly harsh winter. If this were an antelope species, maybe they develop smaller horns and long fragile legs but then the speedy males aren't strong enough to defend a breeding territory so their genes don't continue on to the next generation regardless of their 'success' as individuals.
Third, it helps to remember that when it comes to natural selection there is no 'best' strategy, it just has to be good enough to keep going. Like you said, the cheetah population is always going to be much smaller than the prey populations. The cheetahs don't need to catch every single antelope to survive, they only have to catch some. Because there is going to be variation within the population, some individuals will always be easier prey like the very young, old or sick individuals. So long as the breeding rate keeps up with the rate of predation, then our two species will end up at an equilibrium instead of driving one or the other to extinction.
Lastly, even if things get bumped out of equilibrium for a time, if you look at inter- and intra- species competition across the whole ecosystem, a new equilibrium will be reached eventually. If there is ever a sudden drop in the cheetah population and our antelope numbers skyrocket, at some point there will be more herbivores than plants so individuals will starve. Weak, starving antelope is free food for the remaining cheetahs and other predators whose numbers will likely rise over time due to the sudden jump in food availability. In the reverse case where cheetahs get too numerous, there are likely other prey animals in an ecosystem that cheetahs will eat while antelope populations recover or cheetah maybe some cheetahs will disperse to new areas with higher prey availability.
If you want a fun example of another evolutionary battle, look up sneaker males in rainbow trout. There are two competing breeding strategies within the same species, and neither is likely to ever fully eliminate the other.
