Guinea Pigs (also known as cavies) are a species of rodent native to the South American Andes. They are social inquisitive creatures and make lovely pets. Although they are commonly thought to be easy first pets for children, they require plenty of attention, care and time, and a well-researched approach to their care.

The following information is only a basic overview. It does not cover every aspect of guinea pig care and we strongly advise that you seek further information to ensure the health and welfare of the animals in your care.

Basic requirements

Companionship

Guinea pigs are a social species and need to be kept with other guinea pigs. In their natural habitat, they live in herds and communicate frequently with each other with sounds, gestures, and body movements. Your guinea pigs should be kept in groups of at least two individuals. Make sure that the guinea pigs are desexed or that both animals are of the same sex to avoid having any unintended litters of baby guinea pigs. Desexing your guinea pigs will not only prevent unwanted litters but will also prevent some health problems. For example, in females desexing will prevent ovarian cysts, and in males desexing can prevent or limit the development of a condition called ‘boar butt’ (this is where the muscles around their bottom stretch, this can lead to the accumulation of faecal material in their rectum causing discomfort and health problems).

It cannot be overstated how important it is for guinea pigs to live in stable social guinea pig groups. There is a lot of evidence to show that social interaction with other compatible guinea pigs is beneficial to their health and welfare and also that lack of this is stressful and detrimental. It is important that guinea pigs are socialised early in their lives so that they develop the social skills they need to function well within guinea pig social structures! New animals should be carefully introduced and monitored for aggressive interactions. Particularly, male guinea pigs are more likely to tolerate one another without fighting if they are introduced at a young age. Once guinea pigs have formed social bonds, these guinea pigs should not be separated if at all possible. Even if one guinea pig needs veterinary treatment, ideally at least one of their family should stay with them, as this helps to reduce their stress and helps them cope better.

Guinea pigs should not be kept with rabbits as these two species have different needs and do not make compatible companions. Rabbits may carry Bordetella bronchiseptica (a bacteria that often causes respiratory disease in guinea pigs) and pass this onto your guinea pigs. Another harmful organism that can be spread between the two species and cause health problems is the parasite E.Cuniculi. In addition, rabbits often bully guinea pigs and display sexual aggression towards them; rabbits can seriously injure guinea pigs, particularly with their strong kicks.

Guinea pigs need to live with other compatible guinea pigs.

Housing

It is important to provide these sociable and complex little animals with an environment that is interesting, varied, and safe.

Although they are small, guinea pigs require plenty of space to exercise, the more the better. Provide an enclosure as large as possible; the minimum dimensions for the enclosure of a pair of guinea pigs are 2500 cm² of useable floor space for guinea pigs over 450 g with an additional 900 cm² for each additional guinea pig weighing over 700 g. Enclosures should be at least 25 to 30 cm high. So as an example, an enclosure for a pair of guinea pigs could be 2m x 0.5m x 25cm high to provide the minimum space required but ideally their enclosure should be larger than this. All enclosures should be strong enough to keep the guinea pigs safe from other animals, particularly predators such as dogs, cats, and foxes.

Make sure that the materials used to construct your guinea pigs’ enclosure are durable, non-toxic to guinea pigs, and easily cleaned. The design of your enclosure should also allow for easy cleaning. The enclosure should have a solid floor (wire floors cause discomfort and damage to guinea pigs’ feet) and should be placed in an area that is quiet and peaceful and also free from drafts, chills, extreme heat, and sudden temperature changes.

Guinea pigs can be prone to getting painful and serious foot conditions if kept on wire or hard flooring so it is important to provide them with soft floor covering and bedding. Enclosures should be lined with newspaper and then at least 5cm of soft, nontoxic, nonabrasive, inedible, dust-free and absorbent bedding to provide cushioning and prevent foot problems. Suitable options for bedding include soft grass hay, fleece fabric, and shredded paper. Sawdust or wood shavings can cause respiratory issues and should be avoided. Straw should also be avoided as it does not absorb urine well and the hard stalks can cause injuries.

It is important to regularly change bedding and floor material and clean out the enclosures to avoid ammonia build-up from urine and also to help minimise the attraction of flies to the area. The bedding should be cleaned and changed as required (this is typically once a day). The enclosure should be thoroughly washed and disinfected once a week. Make sure that after disinfection the cage is rinsed well and completely dried out before you add fresh bedding again and return your guinea pigs to their home. Rinse feeders and waterers every day, and thoroughly clean once a week too.

Guinea pigs can be susceptible to fly strike (which can be fatal), so it is also important to fly-proof their enclosure using fly-screen wire or mosquito netting in areas where flies are a problem.

Guinea pigs are also very susceptible to heat stress, and this can be fatal. Therefore, always ensure that they are kept in an area that is well-ventilated, provides adequate shade, and does not become hot. Animals in enclosures, hutches, and cages can die from overheating easily. The ideal ambient temperature for guinea pigs is between 16 to 24°C with a relative humidity of between 40 and 70%; outside of those temperatures/humidity you will need to take steps to safeguard the health and welfare of your guinea pigs. You should consider temperatures of over 26 degrees to be dangerous to the health and welfare of your guinea pigs and take steps to protect them from heat stress. If the day is particularly hot then ideally guinea pigs should be kept in an air-conditioned environment. Guinea pigs can also suffer if it is cold, wet, and windy and are prone to respiratory problems which can be serious. Please ensure that your guinea pigs’ enclosure has areas that are draft free, dry and warm, and if it is particularly cold or stormy please consider moving them inside if they are normally outdoors.

Guinea pigs are prey animals and so they need places to hide where they will feel safe; they need to be able to hide when they are stressed, afraid, unwell, or want some time away from other guinea pigs or people. You will need to provide open space interspersed with enough shelters and hiding places so that every guinea pig in the enclosure has the option for their own separate hiding area, and also a main shelter/hiding place that is big enough for all of your guinea pigs to comfortably rest together inside. You can use hiding places such as cardboard boxes, custom made igloos, wooden boxes, fabric guinea pig beds, tunnels made from PVC piping or, if possible, you can even plant long grasses such as timothy grass for your guinea pigs to make their own tunnels through.

Diet

Guinea pigs are natural herbivores and would spend their time foraging and grazing in small herds in the wild. They need to be fed the types of food they have adapted to eat. Their teeth are continuously growing, which is one of the reasons why they need plenty of roughage to chew; this wears down their teeth and helps prevent serious dental problems. Providing sufficient fibre in their diet is also very important for both their gastrointestinal system and general health.

For your guinea pigs to be happy and healthy, you should:

• Ensure that your guinea pigs have a constant supply of grass and/or grass hay (such as Timothy, Oaten, Barley, or grassy hay). Guinea pigs should not be fed Lucerne (alfalfa) or Clover hay, as these are too high in protein and calcium. The hay that you feed should be available 24 hours a day and of good quality, dry, and sweet smelling. This is paramount in providing a complete diet and encourages the guinea pigs to chew for long periods of time. This chewing helps to wear down their continuously growing teeth and is very important in maintaining dental and gastrointestinal health. The hay should ideally be contained in a hayrack or basket to prevent it sitting on the enclosure floor and getting contaminated by your guinea pigs’ waste and becoming damp, dirty, and mouldy; this is unhygienic and could make your guinea pigs sick.
• Offer a variety of fresh leafy green vegetables & herbs daily. Some examples of these include dark leafed lettuce varieties such as rocket, dandelion greens, snow peas, and herbs such as marjoram, borage, marigold, nasturtium, rosemary, parsley, coriander, basil, and dill. Other foods that are good to fed guinea pigs a few times a week include broccoli, cabbage, endive, carrot tops, Brussels sprouts, kale, silver beet, mint, and fruits such as apples (but with no seeds), mango, and papaya.
• Provide your guinea pigs with a dietary source of Vitamin C because (like humans), guinea pigs cannot synthesise Vitamin C from other food substances. Vitamin C rich foods such as leafy green veggies and capsicums (green, orange, and red) should be fed to your guinea pigs daily. Foods like carrots, kiwifruit, berries, and pineapple are also great as a source of Vitamin C and a tasty treat for your guinea pigs but only feed them a few times a week, not every day, as these foods have quite a high sugar content.
• Make sure that you source grass, herbs, fruits, and vegetables that have not been sprayed by any chemicals, as these could harm your guinea pigs. Lawnmower clippings should never be fed to your guinea pigs as these can cause gastrointestinal blockages and make your guinea pigs very sick.
• High quality commercial ‘Guinea Pig’ pellets (minimum 16% fibre content) may be offered in small quantities, but these should not form the main part of the diet. Although many contain adequate levels of Vitamin C when fresh, this is only when the food is very fresh and within just a few months these foods no longer contain Vitamin C.
• Uneaten food should be removed from your guinea pig’s enclosure after a few hours to ensure that these don’t rot or become mouldy and harm your guinea pig.
• It is important to also know what not to feed guinea pigs, as there are plenty of items that might seem harmless but can in fact cause significant health issues. Make sure you do not feed your guinea pigs the following foods (this is not an exhaustive list): cereals; grains; nuts; seeds; dried beans, corn, and peas; buttercups; garden shrubs (such as hemlock or privet); lilies of any kind; sweet peas; nightshade; oak; avocado; onion grass; onions; potato tops; mushrooms; daffodils; foxglove; rhubarb leaves; and human foods such as breads, biscuits, sweets, sugar, breakfast cereals, dairy products, chocolate, pasta, crackers, or pickled foods.
• If you need to change your guinea pig's diet, please make sure you introduce any changes gradually over a few weeks.
• Provide clean fresh water at all times. Multiple water dispensers should be available and enclosures should be fitted with a water bottle and a small water bowl should be available as well.

It is important that guinea pigs are introduced to a variety of different and healthy foods from a young age, as they may not try or accept new foods later in life.

Please note that it is normal for guinea pigs to eat their soft, nitrogen-rich faeces that are derived from their caecum after they pass them (coprophagy). This does not indicate any kind of dietary deficiency or abnormality and guinea pigs should be allowed to do this.

Grooming

Daily grooming is essential for long-haired guinea pigs to help keep their coat in good condition, and is good for short-haired guinea pigs too. Using a suitable brush, gently remove dead hairs, tangles and pieces of twigs, dry leaves or burrs. During grooming take the opportunity to check your guinea pigs’ health and to ensure that they are free from external parasites. Also check the length of your guinea pigs’ toenails and, if the toenails are found to be overlong, have them clipped by a veterinarian or someone experienced in clipping guinea pigs’ toenails.

Handling

Daily handling and grooming is important in building your guinea pigs’ confidence and for developing friendly and social guinea pigs.

Guinea pigs should be habituated to handling when they are young. Make sure that you handle them carefully, securely, and gently. If they want to, you should allow guinea pigs to retreat and hide. Try never to remove them from a hiding area and force interaction or handling on them; they need to feel that their hiding areas are safe and secure.

Exercise and environmental enrichment

Guinea pigs also need exercise, mental stimulation, environmental enrichment, and the ability to express normal behaviours. The normal behaviours that guinea pigs need to be able to express include social interaction with other guinea pigs, walking, running, tunnelling, exploring, playing, stretching horizontally, retreating to a shelter and hiding, foraging, chewing, gnawing, and jumping.

Environmental enrichment is designed to ensure that your guinea pigs environment positively effects their physical and psychological wellbeing and welfare. The environment of guinea pigs should be made to meet their species-specific behavioural requirements and enable them to express their natural behaviours; this should also help avoid your guinea pigs from developing abnormal behaviours. The following suggestions will help you to provide your guinea pigs with what they need to exercise and express normal behaviours:

• Give your guinea pigs enough space to run about and play.
• Provide them with foraging opportunities such as untreated wicker baskets filled with hay and food hidden around their enclosure for them to find.
• Make their environment varied and interesting with different levels and areas for your guinea pigs to explore; you can use things like ramps and boxes to provide this. You can even make a ‘forest’ out of fleece strips tied to the roof of their enclosure so the strips dangle down and your guinea pigs can push and run through their fleece forest!
• Provide your guinea pigs with toys such as balls made from plastic, untreated willow or dried grass, and small stuffed toys. Ensure that there are adequate toys for each of your guinea pigs to have at least one of their own at any one time. Guinea pigs should also be given chewing items to help entertain them and wear down their teeth (which grow constantly), for example, cardboard boxes, and wooden branches from safe trees such as apple trees that have not been sprayed or treated with any chemicals. A shredded paper pile can provide burrowing, chewing, and hiding opportunities, as well as make a comfortable bed. All items must be safe for your guinea pigs and should be regularly checked and replaced if they are becoming unsafe. Some of the toys and accessories marketed and sold for guinea pigs are, unfortunately, unsuitable and can be harmful, such as wheels and leashes so choose carefully.
• Change the environment in your guinea pigs’ enclosure and rearrange the items in there every week to make the environment more interesting.
• Ideally, provide your guinea pigs with access to a safe outdoor area and give them the opportunity to graze on grass.

Health Problems

Many of the common health problems seen in pet guinea pigs are preventable by good husbandry and feeding practices. The following are some of the common husbandry-related problems seen in guinea pigs:

• Dental disease is very common in guinea pigs, often due to a lack of roughage that guinea pigs could chew and wear down their teeth which are constantly growing. Dental disease can be very painful and cause your guinea pigs to be unable to eat, lose weight, and become ill. Guinea pigs should have constant access to good quality hay.
• Guinea pigs may be susceptible to respiratory infections, often due to poor housing conditions including inadequate ventilation, poor hygiene, and dusty inappropriate bedding.
• Foot inflammation and infections (this is called pododermatitis)can be caused by inappropriate flooring and bedding. Poor hygiene can also lead to foot and skin problems.
• Guinea pigs are susceptible to external parasites like fleas and mites (these can cause intense itchiness, hair loss, and discomfort). Ask your veterinarian about an appropriate preventative regime or treatment for these if required.
• Urinary tract problems such as inflammation, infection and bladder stones are also common in guinea pigs; these are often related to poor diet and poor hygiene.
• Vitamin C deficiency is common if a guinea pig’s diet in inadequate; this can be prevented by feeding fresh foods rich in vitamin C daily.
• Dehydration and heat stress; making sure that your guinea pigs have adequate fresh clean water and that they are kept somewhere where they will not overheat will prevent this.

Signs to look out for that may indicate pain or illness in guinea pigs include:

• Reduced appetite or difficulty eating
• Weight loss
• Drooling
• Drinking more water than usual
• A change in the frequency and/or consistency of faecal pellets (e.g. diarrhoea or the absence of faecal pellets)
• Faeces accumulating around the guinea pig’s bottom
• Changes in urination (for example, a change in the frequency, pain or difficulty urinating)
• Changes in behaviour (such as depression, or aggression in normally non-aggressive animals)
• Squealing or flinching when touched (if this is not normal for that individual, some are quite reactive to being handled)
• Abnormal breathing (e.g. rapid, shallow, raspy)
• Discharge from the nose and eyes and/or sneezing
• Bulging or sunken eyes
• Hair loss or change in hair coat
• Seizures
• Lameness or swelling of joints

Guinea pigs are good at hiding illness and pain. Get to know your guinea pigs’ behaviour; if they are behaving abnormally this may be a sign that something is wrong. If your guinea pig is displaying any of these signs please contact your veterinarian promptly. Guinea pigs should also have regular veterinary check ups; this can help to pick up problems such as overgrown teeth or parasites before these become a major health problem for your guinea pigs.