Dogs that allways chase cats also allways chase other small animals such as squirrles, rabbits, birds, ect. It's an hunting instict from their wolf ancestors. Also, if something turns it back and runs it triggers the hunting instinct. Never turn your back or run from a unknown dog!
dogs chase squirrels, birds, rats, rabbits, chicken etc too. they see them as a prey i guess.
They think the motion of their tails is a toy for them to play with.
they both r enemies................lol
They think they are chew toys...lol