Guinea Pigs are pack animals and very, very social. A guinea pig wants to live with as many of its species as possible. If kept alone a guinea pig will grow lonely and is more vulnerable to illnesses and depression. Contradictory to the common belief, neither a human nor a rabbit can replace a conspecific. Thus guinea pigs should always be kept in a pack of at least two. Even after one guinea pig dies its companion mourns and needs a new partner, preferable at the same age.
Since guinea pigs are very lively and active, they need enough free space to jump and run around. Regardless of being kept inside or outside, their enclosure must be big enough to fit their needs. Only then will guinea pigs have a happy life, otherwise they will get sad, depressed and will become ill easier and faster. If kept in a cage, it must be ensured that the cage provides at least an area of 0.5m² / 5.38 foot² per guinea pig but preferably 1m² / 10.76 foot² per animal. The same applies for an enclosure outside.
A guinea pig needs space to itself, where it can have a rest from the pack. Therefore enough dens and shelters in the enclosure for all the guinea pigs should be provided. An ideal den is about 30 x 30cm / 11.81 x 11.81 inches big and at least 12 – 15cm / 4.72 – 5.91 inches high. Preferably it should have two entrances, so that a guinea pig of a lower rank can escape if a higher-ranked guinea pig enters the den. The roof should be even, to provide space for the guinea pigs to jump on and have an outlook.
Cork tubes of adequate size are good dens and can be cheaply bought in pet shops or DIY markets.
For avoiding boredom, guinea pigs should always have some toys. Ideally these toys serve as brain teaser and are combined with food. A construction manual can be found in the DIY section of this website. The food draws the guinea pigs interest to play with the toy and to find out how it works. Good toys are for example balls with holes for food or small tubes that have to be pushed around to get the food out. Other toys can be bought in every good pet shop.
In addition the cage or enclosure should have a lot of objects for the guinea pigs to interact with. These objects can be larger tubes that the guinea pigs can walk through, wooden bridges that serve the same purpose, hammocks, pillows, ramps or see-saws. Thus the guinea pigs have activities to do apart from eating and sleeping.