The guinea pig or 'cavy' is a species of rodent in the family Caviidae and the genus Cavia.

Despite being called 'guinea pigs' they are not in the pig family or from Guinea.

Guinea pigs originated in the Andes mountains of South America. They do not exist naturally in the wild, instead are domesticated descendants of a closely related species the Cavia aperea.

The guinea pig is an important creature for many indigenous South American people, especially as a food source. But also for customary medicine or religious ceremonies.

The guinea pig has been a popular household pet in Western societies since they were first bought back by European traders as long ago as the 16th century.

They are still very popular as pets today due to their quiet nature, their openness to humans through handling and feeding, and the relative ease of caring for them.

Guinea pigs purr when they are happy, often, like a cat it is when they are being held or petted. They make a whistle noise when they are excited, usually on seeing their owner or when its feeding time.

Grass is the guinea pig's main diet of food, they also need to eat fresh fruit and vegetables.

Guinea pigs on average weigh 0.70 to 1.2 kg (1.5 - 2.5 lbs), and are 20 to 25 cm (8 - 10 inches) long.

Guinea pigs live on average for 4 - 5 years but sometimes as long as 8 years.

In the early 20th century the guinea pig was used in scientific experimentation,  they have now mainly been replaced in laboratories by mice and rats. Although the term 'guinea pig' is still commonly used in English as a metaphor for something being experimented on.

The guinea pig is a popular traditional food dish in many South American countries most notably Peru and Bolivia and areas of Ecuador and Colombia.