Huh, it appears my years of animal skeleton study has been gazumped...
Yes, quadrupeds have kneecaps, and knees, and ankles and all that, they just aren't quite where many people think they are - as Waffles said, they walk on tip toe so the joint in the middle of their back leg is the ankle, and the knee is actually up at the top of the leg, and the hip sort of buried within the body, which is why quadrupeds look as if their 'knees' bend the other way to us - because it's their ankles... Same at the front, the 'front knee' is the wrist, and the elbow up at the top of the leg and the shoulder within the body.
Prey animals walk even more on tip toe than predators, and have the number of toes reduced to reduce the weight of the legs, since the key to really fast running is light limbs and long strides. Except in the case of the cheetah, when a certain amount of being able to dislocate your spine also comes into it. There's a theory that giraffes didn't evolve tall to browse the top of trees, they evolved long legs to run, and the neck had to follow in order for them to be able to drink...
Cows, of course, have kneecaps, and for some reason, I've always found them amusing when I find one in an assemblage. I don't know why.
Any tea going? I don't like to jinx myself, but my back has felt way better today. Just need to try and make myself take it easy for the next fortnight, then I have a week off...