Guinea Pigs: Care and behaviour

Guinea pigs are often chosen as children's first pets. They aren't very demanding, and are easy for children to handle, once they learn the technique. Yet there's a strong case for guinea pigs as pets for adults. They're great stress-busters. and it's relaxing to watch them interacting with one another and grazing in the garden on a sunny day. They aren't over-fond of being cuddled by humans, but they do like to greet their owners with excited squeaks, especially around feeding time.

Guinea pigs may only live four or five years, though if they're well looked after, they can live for seven years or longer. True, they aren't very demanding, but they do need daily care, and are all too often neglected when young owners grow out of them. If you feel you or your children have grown out of your guinea pigs, or are just too busy to give them the care they need, find a responsible friend or neighbour who wants to take them on, or an animal welfare charity may find someone for you.

Guinea pig behaviour

Pet guinea pigs are descended from wild cavies, which are social animals, living in small groups which are made up of a male, females, and their babies, or pups. Bachelor groups live nearby, and females may mate with one of the bachelors, then either stay with him and set up a new group, or return to the main group to have pups. Wild cavies are prey animals, so run for cover if startled, and they keep their eyes open a lot, even when dozing, so they can respond fast to danger.

Pet guinea pigs are less aggressive and more sociable with one another than their wild cousins. They still behave in similar ways, for example, they need to be with other guinea pigs, and they run to a hiding place when startled, 'Social' animals live in groups, so suffer if kept alone. 'Social' doesn't always mean that animals like to be handled by humans, in fact, because guinea pigs tend to startle easily, they can become very stressed out if handled too much, and they aren't suitable pets for younger children. They're good pets for teaching children the benefits of patience and observation, because they become tame more easily if you go slowly, rather than trying to pick them up right from the start, and it's interesting to watch how they interact with one another. They don't like having lots of children crowding round them and trying to grab them, This is a recipe for accidents, and can stress guinea pigs a lot, especially adolescents, so guinea pigs are really only suitable for responsible children who can understand what their pets are feeling.

An entertaining trait of guinea pigs is that they like to talk to one another a lot, and they talk to us when they get to know us. They oink, or 'wheek' when they're happy and excited, chatter when they're annoyed, and 'purr' when they're happy, as well as when they're wondering what a strange sound is. Worried 'purrs' tend to sound deeper.  You can also tell a lot about how your guinea pig is feeling from body language. Happy guinea pigs sometimes 'popcorn', or do little vertical jumps. This can happen if they're outside in long grass, or if you've just changed their hay, and it may be a way of checking out their surroundings. Guinea pigs can also stand on their hind legs to see what's going on. If what they see or hear is scary, they'll run for cover. They aren't burrowing animals in the wild, though they may use another animal's burrow to hide in. Guinea pigs may also mark territory, by dragging their bums along the ground. You're especially likely to see this if you've just cleaned their cage and given them fresh bedding.

Depressed guinea pigs tend to keep still and stay quiet. If your guinea pig suddenly looks depressed and isn't eating, this is a sign that you need the help of a vet, and fast.

Choosing a guinea pig

Guinea pigs in rescue centres and pet shops are usually crossbreeds, so the main thing to look for is a healthy, alert animal. Remember that they're social animals, so you'll need more than one, if you have no other guinea pigs. Two young females should get on, especially if they're related. Males are more likely to fight, though most guinea pigs will get on with others they've known since they were youngsters. You'll need to think about what to do with baby guinea pigs if you buy a young male and a young female. 

Adult guinea pigs can be grumpy and even aggressive if you put a strange adult guinea pig in with them, especially if they're both male. However, people often want to rehome adult guinea pigs which have always lived together peacefully since they were youngsters. 

Keep an eye on your guinea pigs when you introduce new companions, until you're certain they do get on. Try putting them near one another in separate cages for a few days, so they get used to one another's smell. Then try introducing them in a big run, keeping an eye on them at first, only putting them in a smaller cage together when they seem relaxed and peaceful with one another. Guinea pigs that are wary of their companions will warn them off by chattering at them. They often groom one another if they get on.

Only keep entire adult males and females together if you have homes for the potential babies, and only put one male at a time in the same cage as a female or females. Remember that wild cavies tend to live in groups with just one male. Guinea pigs won't pair off if you try putting two males and two females together, one male is likely to want both females!  If you neuter your guinea pigs, you have more freedom to house them without worrying about unwanted babies.

Pure-bred guinea pigs can be found at agricultural shows and exhibitions where specialist breeders sell and show their animals. Cross breeds can be just as entertaining, if not more so, and it's only worth spending a lot of money on a pure-bred guinea pig if you want to take up showing as a hobby. There are three main kinds of guinea pig coats: short, smooth coats; the Abyssinian short hair in rosettes; and long straight hair. You'll need to groom long-haired guinea pigs, and be especially careful to keep them clean, so short-haired guinea pigs are a more sensible choice as pets for children. There's a wide range of guinea pig colours and colour combinations, including albinos with white coats and pink eyes, which need more protection from the sun.

Housing

Guinea pigs live in groups in the wild, and prefer companionship in captivity, but you need to choose their cage mates carefully, because they have to get on really well. They can't run away from a companion they don't get on with in a cage. Two males will sometimes fight, especially if they're competing over a female, and females may also fight, until they work out who's boss. It's always worth having a spare cage just in case you need to separate your guinea pigs, if one is ill, has just given birth, or if they squabble, for example.

A pair of guinea pigs needs a hutch around 120 cm long, by 60 cm wide and 50cm high, with a wooden-fronted partition at one end for sleeping, and 18mm wire mesh across the rest of the front. Smaller hutches will get soiled faster, and you're more likely to have fights, though you can have a smaller cage for the night if you can let your guinea pigs out in an indoor or outdoor run in the daytime. Guinea pigs can be very entertaining in groups, but you need to give them a lot of space with plenty of hidey holes, and most people don't have enough space for keeping guinea pigs in very big cages. An alternative is to keep guinea pigs in pairs or threes, and let them meet in large spaces, when you can watch them.

Front-opening cages are kinder than cages opening at the top, because it's less frightening for your guinea pig to see you at its own level, than to have you pick it up from above. You need two doors, one for the sleeping quarters, and one for the living quarters.

Put the hutch in the part of your shed or garage that is most draught-free. Paper can be placed on the hutch floor and covered with hay for bedding. Sawdust and shavings should not be used as they can cause breathing and other health problems. Guinea pigs need a chewing block or twigs to wear down their teeth, which can grow too long otherwise.

Soiled bedding should be removed daily, and you need a proper clean-out of the whole cage every week. Cleaning the cage is very important to avoid skin problems and infestations. Wire mesh on the floor allows droppings to fall through, but hurts their little feet, so is not a good idea. You can make or buy cages with trays for the bottom of the cage that slide out, for easy cleaning. The tray only needs to go under their living quarters, because they don't usually wee in their sleeping quarters - though you still need to clean the sleeping quarters regularly to avoid infestations. Ideally, you need a spare tray for the living quarters, so you can take one out, clean it with disinfectant and leave it to dry, and put in the dry one from the day before. It's kinder to put your guinea pigs in a separate run when you give them their weekly clean - they don't like being disturbed, especially if they are in their 'safe' area.

Guinea pigs benefit from exercise outdoors in a secure run during the summer. They must have a shelter in their run to protect them from rain and wind, and give them more than one hiding place if it's a very big run, so they feel safe. You can use cardboard boxes to give them temporary hiding places when the weather is fine. Lengths of drain pipes give them waterproof shelter, and you can also give them plenty of hay to burrow and hide in. The run should be sturdy enough to give protection from dogs and foxes. Put the run in partial shade so the guinea pigs don't get too hot, and find somewhere in your garden with total shade for albinos. 

Guinea pigs like exercise in the winter when it's too cold to allow them outside, so you can set up a secure indoor run for them. They will need a shelter to hide in, just as they do with the outdoor run, to keep them out of draughts and because they are shy, so like to be able to hide away if they hear sounds that startle them.

Feeding

Guinea pigs need daily doses of vitamin C to stay healthy, so give them fresh vegetables twice a day if they don't have access to grazing outside. They eat fresh green vegetables like dandelions or cabbage, and root vegetables such as carrots. You can also give them fruit, though in small amounts. Some wild plants, like foxglove, bracken and buttercup, are poisonous for guinea pigs, and avoid giving them onions. Some people give their guinea pigs vitamin C supplements, but these aren't normally necessary for guinea pigs given enough fresh fruit and vegetables. There's a risk of overdosing your pet if you administer supplements without checking the dosage with a vet - it's possible to have too much of a good thing!

Guinea pigs should also have hay and special guinea pig pellets available at all times, as well as fresh water. Pellets are better for their teeth than 'muesli', and better nutritionally, because guinea pigs may just pick out the best bits if they can pick and choose from muesli. You need a heavy bowl that won't get knocked over and is easy to clean, for both their water and their food. Plastic bowls will tend to get knocked over. It's also worth providing more than one food bowl so that one pig can't 'hog' the bowl. 

Guinea pigs, like rabbits, eat their own droppings, which is their way of chewing the cud. It allows them to extract maximum nutrition from their food, especially B vitamins. Like rabbits, they have hard droppings, which are not eaten, and soft droppings, which they find yummy, even if you don't!

Health

You can prevent a lot of health problems by making sure your guinea pigs have something to chew, proper food, a clean, roomy, draught-free home. Dental problems are very common in guinea pigs, because their teeth grow continuously, so they need something to chew, to help wear down their teeth.

Giving guinea pigs plenty of room makes it less likely they'll be too rough with each other. If you think they're fighting, it's worth checking for any scratches and cleaning them with mild antiseptic. Ears are commonly injured in fights. If fights are frequent, it's safer to separate the pigs, only allowing them together under supervision.

Guinea pigs can be troubled by skin complaints such as lice and mites, and you'll need to take them to the vet if you see signs of these problems. Skin infections are most commonly found in young guinea pigs, and youngsters may well become infected in pet shops, so it's worth getting recently purchased guinea pigs checked out by a vet, just in case.

Sometimes guinea pigs suffer from eye trouble caused by hay or other foreign bodies getting trapped in the eye, and you may need a vet visit to sort this. It's worth seeing the vet if any eye trouble persists for longer than a day, because of possible damage to the eye frm trapped hay or whatever, or the eye trouble may be a sign of other problems. Guinea pigs do secrete a milky fluid from near their eyes, and this helps them to groom, it's not a sign of illness.

Older female guinea pigs often develop ovarian problems, especially cysts, and some vets recommend spaying, involving removing the ovaries, as a preventive measure. If you decide on a spay, you'll need a vet who has a lot of experience with spaying guinea pigs, perhaps one who works with a rescue.

Handling

Guinea pigs are shy and need very gentle handling. They will wriggle if they are nervous, so you have to pick them up with both hands, and be careful that they don't fall and hurt themselves. A guinea pig you've just brought home is likely to be nervous of you at first, and youngsters are especially skittish. Give your new guinea pig time to get to know you before you start picking it up. Talk to it quietly so it gets used to the sound of your voice, and tempt it with titbits. You can try stroking the guinea pig gently when it comes to you, talking quietly, and offering a titbit with your other hand. When your guinea pig has got used to you (which may take a few days), then you can pick it up and put it on your lap. If you sit on the floor, it can't fall. It will get frightened if you squeal that it's tickling or nibbling you! Keep calling it with a titbit and handling it for a very short time every day, so it gets used to you, and you'll eventually find it will come to greet you in the hope of special treats.

Breeding

Guinea pigs breed freely, so if you put an adult male in with one or more females, you're likely to get little guinea pigs. Females have a long gestation period of from 60-65 days, and the young are born with all their fur, unlike rabbits, which are born blind and hairless. Litters are usually small, from one to four babies. You need to remove the male, because he's likely to want to mate with the new mother, and it isn't good for her health to have another litter so quickly. You can keep other females in with her. Adult females are usually gentle with other females' pups, and may even help to care for them.

Young guinea pigs are enchanting creatures, but beware of overcrowding, and keep the sexes separate as soon as they can be taken from their mother. You can sex a young guinea pig by gently turning it onto its back and pressing (very gently) above its genitals to see if it has a penis. Females can breed from as young as a month old, males from two months, so you need to separate them just after weaning, at three to four weeks old. Do this even if you want to breed them, because they aren't adult and ready for breeding until they are six months old.

Article by Gillian Harvey and Alison Lever

Further reading:

Minarikova, A., K. Hauptman, E. Jeklova, Z. Knotek, and V. Jekl (2015) Diseases in pet guinea pigs: a retrospective study in 1000 animals. Veterinary Record Volume 177: 200, July 2015

Zipser, B.; Schleking, A.; Kaiser, S.; Sachser, N. (2014). Effects of domestication of biobehavioural profiles: a comparison of domestic guinea pigs and wild cavies from early to late adolescence. Frontiers in Zoology, 11, 30.

See also:

• News and research: rabbits and rodents
• News and research: Health, disease and physiology, rabbits and rodents
• Reviews of books on rodents, including guinea pigs

• Chinchillas: Care and behaviour

• Chipmunks: Care and behaviour
• Gerbils: Care and behaviour

• Hamsters: Care and behaviour

• Rats: Care and behaviour