If your sweet guinea pig has a habit of making a lot of seemingly random noises, then it's likely because he's trying to communicate something, whether to you or to anyone else around him. Cavies can be pretty social and "talkative" animals when the mood strikes. The better you can understand your guinea pig's noises, the better you can understand him in general.
If your guinea pigs makes a jarring high-pitched squealing or squeaking noise, she may be sending out an alert of sorts. She for whatever reason believes that something threatening is on the horizon, and is doing her duty by making sure that everyone else is aware of it too. Squealing, however, also can occasionally indicate physical pain and discomfort or the desire for your undivided, immediate attention.
Chattering of the Teeth
The chattering of a guinea pig's teeth is another type of warning. It often denotes a guinea pig that is irked or irritated by something or someone. If your guinea pig chatters his wee chompers at you, then it's probably your cue to leave him alone for a while -- pronto. The chatter could mean something as basic as, "The way you are holding me is uncomfortable" or "I want you to stop petting me right now. I just don't feel like it at the moment."
A "wheeking" sound is one that is rather similar to an extended whistle. If you hear this sound coming out of your cavy, it probably means that he's really happy about something, whether your mere presence or the idea of his upcoming yummy meal. This sound also sometimes is an attention-seeking one, however.
Felines aren't the only fluffy purring animals out there, because guinea pigs frequently do it too. A low and rumbling purring sound, just like in cats, is often a sign that a guinea pig is feeling comfortable and serene -- everything is just fine in his world. However, if the purr is higher and your guinea pig's posture seems rather tense and rigid as he's making the sound, it may mean a bevy of unpleasant emotions, such as annoyance, fear or confusion.
If a rumbling sound is especially low and deep, it probably isn't a purr but rather a mating behavior. If a male guinea pig rumbles, then he may be trying to attract the attention of a female cavy for mating purposes. You may also notice him engaging in a peculiar "mating dance" as he rumbles -- one that involves a little hip swaying.
A light murmuring sound is usually a rather positive noise. If your guinea pig "murmurs" at you, it means he's probably pretty fond of you. Female guinea pigs also frequently murmur or coo at their young offspring.
A loud shrieking noise signifies a poor guinea pig that is either suffering in pain, or that is really frightened by something. If you hear this sound, pay close attention to your cavy to make sure that he's OK.
Michael Blann/Digital Vision/Getty Images