Why do dogs and cats love laser pointers?

We bought a laser pointer from petsmart and ever since my dog has been very paroniod about it she lloks everywhere for it if Im holing the remote she will look around the the mysterious res dot. And my cat is not as bas but when the dot shows up he goes crazy but then when we put it away he could care less. We have another dog that cant see it or doesnt care. So my question is why does one dog go paraniod over it one dog doesnt care at all and the cat only caes when it shows up. and my other question is why do they chase the little red dot anyway?

well i do have cats that always chase around the laser. i guess it depends on what kind of type ur dog or cat is. the yougner cats or dogs are probably moire playful then older ones. so maybe the dog that is all paranoid is a playful youngster dog and ur cat is probably and aggresive cat... a hunter. i can see ur cat being an outdoor cat. and ur other dog who doesnt care. maybe hes just old and he cant really see that well and lost his playfullness. but i dont know ur cat and dogs so i could be right i could be wrong