- The guinea pigs are a domesticated species of South American rodent
- They have a robust body with short limbs, large head and eyes, and short ears. The feet have hairless soles and short, sharp claws
- Coloration is extremely variable: the coat may be white, cream, tan, reddish or chocolate brown, black, or a combined pattern.
- No natural population of this species exists in the wild. Guinea pigs were apparently domesticated more than 3,000 years ago in Peru
- The common pet breeds weigh between 700 and 1,200 g (1.5 and 2.6 lbs) when full grown and measure between 20 and 25 cm (8 and 10 in) in length
- They live an average of four to five years, but may live as long as eight
- They startle extremely easily, and either freeze in place for long periods or run for cover with rapid, darting motions when they sense danger
- When happily excited, guinea pigs may repeatedly perform little hops in the air
- Guinea pigs are good swimmers
- The guinea pig’s natural diet is grass; their molars are particularly suited for grinding plant matter and grow continuously throughout their life