Guinea Pig Not Eatting

Question
My daughter's guinea pig isn't eating (very little) and doesn't come out of his igloo as much as he use too.  We looked at his teeth, they don't look bad.  Any help you can give us will be greatly appreciated.

Answer

Cavy teeth side view  

cavy teeth front view   Loss of appetite is always a bad sign. You don't say how old he is, but sometimes this is an indication of an old pig that's beginning to fail.  The problem with the teeth is often not the front teeth but the back ones that we can't see.  Just as with humans the front teeth are just used to bite a chunk of food, but the chewing process happens in the back teeth.

If there's a malocclusion or misalignment in those back teeth they have problems chewing and digesting their food. This doesn't happen often, but is a possibility. Here's a picture of how the teeth are aligned and you can see how important it is that they're making proper contact.

If there is a malocclusion a vet can file the back teeth to help them chew. The only problem is that there's no guarantee it won't happen again.

If he's willing to eat a piece of carrot or lettuce that's a good sign that he may not have a problem with his teeth. And sometimes the weather can affect the appetite as well.