To dream of a guinea pig represents an aspect of yourself that does everything for someone else. It may also reflect your need to be completely responsible and attentive for someone else's needs. Looking after someone that is not intelligent enough to look after themselves.
Guinea pig dreams are common to new born mothers who fear leaving their child alone or with someone else.
Negatively, a guinea pig may reflect behavior that is smothering, pampering, or enabling laziness. It may also reflect a fear of not being attentive enough.
Example: A new mother was having nightmares of guinea pigs being sacrificed by a Satanic woman. In waking life she was fearing being a bad mother if she left her new born child with anyone else at all. The guinea pigs reflected her need to do everything for her new born son at all times.