guinea pig very lethargic

Question
we have two guinea pigs both bought at the same time.Apparently they were both supposed to be female but one is more active to the other. The definate female is not her usual self today she is being quiet and lethargic. she is drinking plenty of water and is getting plenty of food and vitamin c. If you have any ideas please can you let me know.

Answer
How old are your guinea pigs? Are you positive that the other guinea pig that is more active a female as well? I would take the other guinea pig to a vet and make sure that the other guinea pig is a male. If it's a male than it's quite possible that she may be pregnant if it's a female than your guinea pig that is acting abnormal may be stressed out. Is there anything that you have recently changed in the cage or around the cage that could cause the guinea pig to become stressed? If you haven't changed anything that would cause stress then I would take her to the vet for a check up as it's really not normal for a guinea pig to be that quiet and that lethargic.

http://cavyspirit.com/sexing.htm