Rats sure are chirpy little creatures, but not all of their sounds are within our hearing range. Actually, they make a bunch of ultrasonic vocalizations that we can't hear naturally. These high-pitched sounds usually crop up during social interactions or as a response to their environment — think of it like their secret chat tool. For instance, when rats are happy or playing, they often emit these ultrasonic chirps, which is quite fascinating, isn't it? Now, onto the sounds we can hear: bruxing is when rats grind their teeth together, creating a bit of a chattering sound. It's usually a sign of contentment—kinda like a cat's purr—but can also indicate anxiety. Screaming, on the other hand, is exactly as distressing as it sounds; it typically means the rat is in pain or severely frightened, definitely a sign to consult your vet. Hissing is another stress signal, showing irritation or fear. As for squeaking, yes, rats do that too, and it's often a sign of excitement or mild stress. It's not exactly like guinea pigs, whose squeaks can range from excitement to asking for food—it's a bit more about immediate feelings or reactions in rats. So keeping ears tuned to these nuances makes understanding your little buddy so much easier. Keep an ear out for these sounds, and you'll get a pretty good sense of how your rat's feeling!