This text is also published in our On The Hop booklet.

Many of our readers may have guinea pigs at home; this short section will give you a small insight into their care and the common problems they face.

Guinea Pigs belong to the rodent family – Histricomorphs. They originate from South America and may also be referred to as cavies by fanciers. They were introduced to Europe in the 16th century as they were sold in the meat trade.
They have a 4-7 years life expectancy. They are small, compact and “chatty”, fun to watch and be around.

Their white-coloured incisors are ideal for gnawing so wooden branches should be provided for this and enrichment. All their teeth are open rooted and continuously growing which means they must be worn down or they will overgrow very quickly just as with rabbits. Guinea pigs have a rapid GI transit time and are designed to eat a high fibre diet to remain as healthy as possible.

Sexing guinea pigs

Males have a round opening on the end of their prepuce and the penis can be fully extended with gentle pressure – older male guinea pigs may need help keeping this area clean and free from infection. Male guinea pigs’ testicles can be easily palpable and will look like a bulging area round the back end, they will be covered in fur and not hairless like in rabbits.

Females will have a Y shaped opening with a V shaped vagina, with the anus directly below.

Both sexes have 2 nipples.

There are lots of varieties of guineas pigs in the pet trade now, the most commonly kept being English (short haired), Abyssinian (rosettes on longer coat), Peruvian (long haired), Teddy and Rex (short, bristly coats).

Guinea pigs are highly sociable animals and must never be kept alone. In the wild they would live in social groups of 20 plus. Most owners will keep same sex pairs, and this normally suits the guinea pigs fine, although males can still have some squabbling so must be neutered. If groups are being kept then they need to be harems – one (neutered) male to a group of females, if more than one male is within a harem the males will be very aggressive and territorial with the females – even if neutered. When keeping more than two guinea pigs there should be adequate bolt holes/space for nesting/resting so the guinea pigs can find space away from one another if need be. Guinea pigs love tunnels and places to hide.

Guinea pigs should never live with rabbits as they can be at risk of injury from kicking, mounting and aggressive behaviour. Rabbits also carry bacteria called Bordetella which can be fatal to a guinea pig if caught. It is very outdated to keep both together – it was seen as an easy option in the past, as owners knew the animals should have a friend and vets were not as keen to neuter. It seemed to be common place to keep them together, it would have caused stress to both animals and is poor welfare for both animals as they have no way of communicating with one another. Housing guinea pigs needs to be considered carefully if they are being kept outside, as they cannot tolerate wet, cold, draughty environments. They should have a hutch no smaller than 4ft x 2ft (1.25m x 1m) and access to an exercise area of 6ft x 4ft (2m x 1.25m). They should also have tunnels and pipes to hide in. Guinea pigs will not dig like rabbits but will shear any grass short in very little time, so a run attached to a pipe would be a good idea so that the run can be moved onto fresh ground to allow regrowth. This will stop their area becoming wet and muddy. As guinea pigs are so low to the ground, care should be taken to make sure they are not getting wet/muddy when outside – especially the long-haired varieties as they can get matted and waterlogged quickly.

Indoor housing should be as large as possible and ideally on one level or with wide/sided ramps to allow guinea pigs to access upstairs areas safely if available. Modular cages such as the C&C range are useful as they can be made up in shapes to fit the area available and are not bulky. They are easy to store if guinea pigs move outside in the summer months. They should not be housed next to radiators as temperatures over 26 degrees can cause heatstroke. They should ideally be housed away from other pets inside the home and not in a child’s bedroom, somewhere quieter would be best suited.

Guinea pigs being prey animals can be fearful of handling, so all handling should be gentle, supportive and done on floor level if by children, to avoid guinea pigs being squeezed, jumping or being dropped. Sitting with them and letting them come to you is the best option. If being lifted, guinea pigs should be supported cradled into the body and should not be scruffed or grabbed.

Guinea pigs cannot make their own Vitamin C from their food, and without it will be very unwell. Good quality guinea pig food contains the right amount of Vitamin C to keep them healthy, so make sure you chose a good brand, like Burgess. Food should be stored as per the manufacturer’s instructions and used by the use by date to ensure correct Vitamin C levels. There is no need to provide a supplement if they have a good quality food, and hay. Fresh plain drinking water should always be available also.

A variety of their daily veg can contain Vitamin C also.

Guinea pigs should be fed with similar food ratios as rabbits – 85% hay/grass/forage, 12% veg, 3% pellets.

As guinea pigs are designed to graze for most of the day, inadequate diets can cause serious dental disease, guinea pigs are also prone to GI tract problems such as bloat and gut stasis, the same as rabbits. Guinea pigs will eat all veg safe for rabbits with the addition of peppers for more Vitamin C. Care should be taken with veg high in calcium such as spinach and kale, as guinea pigs can be prone to bladder issues, such as stones or sludge, so large amounts of veg high in calcium should be avoided.

The RWAF do not condone breeding of rabbits or guinea pigs. However, if you do intend to breed from your guinea pigs, this should be done when they are young. This is due to the pelvic bones fusing in guinea pigs older than around 10 months, if a female guinea pig is introduced to an unneutered male after this age, it is unlikely she would be able to give birth naturally and would need a caesarean section to safely remove the young, if guinea pigs do have an early litter they will be able to give birth naturally from then on.

A guinea pig has a longer gestation period than a rabbit – at on average 63 days, the young will be born fully furred with eyes open. They are weaned off mum at around 3 weeks old.