Beyond a simple matter of terminal velocity, survival is also a matter of the maximum speed at which a creature can survive a stiff impact... and that also varies with the size of a creature! An object's strength is proportional to the length scale squared, but the amount of impulse required to stop the object is proportional to the mass, which is proportional to the length scale cubed. The larger the object, the more a collision with a sturdy object at a given velocity damages it.
One can also consider the xenobiological implications of this property of an animal. If, on some planet, the atmospheric pressure/gravity ratio is high (one would find this on large planets, particularly those with low density) then larger animals will be able to survive terminal velocity collisions. This could either make the creatures grow bigger or allow more of them adapt to being able to fall an essentially unlimited distance... or both, for different creatures in a given ecosystem.
(In response to a defunct writeup) I know this is more specific than what you were talking about, but a physically healthy adult cat is capable of flipping itself over to land feet downward, often before it has fallen one meter. My thesis advisor actually carried this experiment out, dropping his Tom onto cushions sufficiently soft that a head bonk wouldn't have harmed it. I only wonder how he managed to convince it to let him pick it up the second time.
The physics of this are comewhat counterintuitive.