Imagine this: Your cat is perched at the window sill, stiff postured and staring out the glass panes. Her jaw starts to open slightly and then begins to vibrate at a fast speed, letting out an interesting sound. Her tail begins to twitch excitedly. But don’t worry as this is completely normal for your furbaby. This fast and intense teeth chattering behavior can often be observed when your feline friend spots a bird or other animal through a window and might be a sign of frustration because they cannot get to their prey. Behaviorists also say that this behavior is a form of excitement or your kitty’s way of performing the act of killing while in the absence of performing the actual behavior. Read this article to learn another possible meaning behind the chattering behavior of cats.