Purchasing a Guinea Pig

You can readily find cute guinea pigs for sale, or you can adopt a guinea pig. But there are many types of guinea pigs, so it is good to know what you want. If you plan to show then you want one that matches the show standards as closely as possible. If you plan to breed then make sure it is the proper age and with the desirable characteristics. But if you want a pet, then you will want a good disposition, and will have to decide how much maintenance you want to do based on its type of coat.
The most important thing though, is choosing a guinea pig that is fit. A young guinea pig, about 5 to 8 weeks old and completely weaned from its mother can be ideal, but even an older pet guinea pig can make a good companion. A healthy guinea pig should feel full and solid, have bright eyes, good sound teeth, a dry nose and clean ears, a healthy coat with no hair loss or thinning fur, and the nails on its small feet should not be splaying out in different directions. Observe the guinea pig in its cage. It should be active with a lively spirit and be able to run in a swift and smooth manner.
Guinea pigs are social animals and either sex will make a good pet. Males do get a little larger and can be somewhat more active. Also as males reach sexual maturity they can put off a bit of an odor, but it will go away if you have your pet neutered. If you plan to buy more than one, two females would be the better choice since males that have not been neutered will almost certainly fight (especially if there are females around). But if they are neutered there is generally no problem.