[pc86]

Eh, sort of. You do that if you're working out, because you're trying to maximize performance.

Most living beings aren't trying maximize performance, they're trying to maximize survival. That crouch gives away that you're about to jump, and it allows prey to avoid you more easily or predators to adjust their attack to counter for it. A rabbit trying to get away from a predator simply bounds away in its given direction without giving away what its doing.

[nilamo]

My experience seeing animals is apparently different from yours. The anticipation/tell is very clear for a wide range of animals... Birds squat down before taking off, cats hunker down to the ground before pouncing, etc.

Even the human jumping example again... Suggesting people only bend their knees for performance would mean the "normal" way of jumping involves keeping your legs straight at all times and using your ankles/toes for all your thrust?