Animals have a very sensitive connection to the earth and the planet's gravitational and electro-magnetic fields. Putting them in an environment simulating weightlessness changes all that. Cats won't be able to land on their feet without knowing which way is up or down. Snakes seems to just coil around in a really weird ball. Frogs kick their legs out, probably trying to escape the weird feeling, but they end up just flailing around in zero gravity. But we have to wonder why they would let animals up in space if their little hairs and fur would fly around, possibly getting stuck in the machinery? Practical or not, these animals still made the trek to simulated 'space', and their reactions are pretty strange.