The Rex Guinea Pig | Breed Facts and Essential Care Guide – Home & Roost

The Rex Guinea Pig | Breed Facts and Essential Care Guide

The Rex Guinea Pig | Breed Facts and Essential Care Guide

Jess Faraday |

When you go to adopt a guinea pig, you'll find there are a lot of different guinea pig breeds. The Rex guinea pig is amongst the most beloved, and it's easy to see why.

All About Rex Guinea Pigs

A dark brown Rex guinea pig, facing to the right.
Image by Jolly Sunshine, under Pixabay license, via Pixabay

The Rex guinea pig is one of the most loved guinea pig breeds. From its easy care short hair to its mellow personality to its delightful "fuzzy potato" appearance, when it comes to pets, it's hard to go wrong with a Rex.

The History of the Rex Guinea Pig

The guinea pig originated in South America. It is believed to have been domesticated around 5,000 years ago. They were a favourite of the Incas, and have lived side by side with the people of the Andes as both pets and livestock for a very long time.

Not much is known about the history of the Rex guinea pig in specific. However, it is believed that Spanish explorers brought guinea pigs back to Europe from South America in the 1530s.

The Rex Guinea Pig breed is not recognised by the American Cavy Breeders Association, but they are recognized by the British Cavy Council.

The Appearance of the Rex Guinea Pig

A brown and white Dutch patterned Rex guinea pig facing forward.
Image by Jolly Sunshine, under Pixabay license, via Pixabay

"Rex" means "king," and owners of Rex guinea pigs would probably agree that the Rex is the king of breeds. But when it comes to animals--cats, rabbits, and yes, guinea pigs--"rexed" fur has a special meaning. "Rexed" fur means fur that lacks guard hairs. This is a genetic mutation that affects many different mammals.

Guard hairs are longer hairs that are surrounded by multiple shorter hairs. The guard hairs protect the skin from abrasion and help to make the animal's coat more waterproof. A "rexed" coat is comparatively bristly and wiry. You might also find rexed animals with a curly coat and curly whiskers, like the Cornish Rex (or Devon Rex) cat.

Some people find animals with a rexed coat to be less triggering to allergies, though rexed animals are not technically hypoallergenic. The Rex guinea pig's easy-care coat grows to a mere half inch (1.27 centimetres) in length, and is sometimes curly along the belly.

Some people describe the Rex guinea pig as having a hedgehog like appearance, while others may describe Rex guineas as fuzzy potatoes.

Rex Guinea Pigs and Teddy Guinea Pigs

A grey and white Teddy guinea pig, facing forward and nibbling on greens.
Image by Jolly Sunshine, under Pixabay license, via Pixabay

Rex guinea pigs look similar to teddy guinea pigs, which also have a bristly coat. However, each of these breeds' distinctive coats come from a different genetic mutation. Here are a few quick ways to tell the difference between the Rex guinea pig breed and the Teddy guinea pig breed.

  • The coat of a Teddy guinea pig is slightly softer than that of a Rex guinea pig. A Teddy guinea pig's softer coat is often described as "bouncy," while that of a Rex guinea pig is "coarse" and "springy."
  • Rex guineas have fur that grows toward the back. If you brush it forward toward their head, it springs back upright. The fur of a teddy guinea pig, which grows toward the front, will lay flat.
  • A Teddy guinea pig has a "fringe" growing above its eyes. This is where the forward-growing hair meets the backward-growing hair. A Rex guinea pig doesn't have this fringe.

Colour Variations of the Rex Guinea Pig

Some have described the Rex guinea pig as "potato looking," and it's true; some Rex guineas are the same medium brown as everyone's favourite tuber. But, like many guinea pig breeds, the Rex guinea pig comes in a variety of colours, including:

  • Gold
  • Chocolate
  • Red
  • Cream
  • White

Rex guineas can also have coat patterns containing multiple colours, like agouti or Dutch.

How Big is the Rex Guinea Pig?

The Rex guinea pig is one of the largest guinea pig breeds overall. Adults can measure up to 18 inches from nose to tail.

The Rex Guinea Pig's Personality

Like the large breeds of many mammals, the Rex guinea pig has a mellow, pleasant temperament. People have described the Rex guinea pig as "sociable," "even-tempered," easygoing," and "friendly."

Of course, as with any animal, every guinea pig has its own personality. Moreover, the past experiences of any guinea pig can affect its behaviour and the way it relates to people and other pets.

Caring for Rex Guinea Pigs

Their short, coarse coat makes grooming Rex pigs a bit easier than grooming some other breeds. But all guinea pigs need a clean, spacious enclosure, a proper diet, plenty of exercise, and lots of socialization.

Cage Size

When choosing an enclosure for your Rex guinea pig, size matters. The larger enclosure you can provide for your cavy, the better.

Guinea pigs are curious creatures, and need plenty of room to explore. Like rabbits, guinea pigs forage in the wild, and pet piggies like to forage, too.

Cavies need their exercise, just like all of us. The more space they have to move about, the easier it will be for your piggies to stay fit and healthy.

As much as guinea pigs like company, no one likes to feel cramped. More space means less stress for your cavies, which can mean less fighting.

On top of that, a larger enclosure will be easier for you to clean.

Hutch Setup

A great guinea pig enclosure has both living space and exercise space.

Living Space

It goes without saying that the larger your total living space, the better. For two cavies, that means a minimum of 10.5 square feet, or 27 inches by 56 inches.

What about just one guinea pig? Well, guinea pigs are social animals. In the wild, they live in herds. Like rabbits, guinea pigs need a friend, otherwise, they get lonely. So for this reason, we recommend keeping more than one at a time.

In addition to being spacious enough, your guinea pig's enclosure needs to be safe from predators and weather. If your enclosure has levels, take care to build in such a way to prevent falls. Avoid glass aquariums; cavies need plenty of fresh air circulation.

A hutch makes an excellent living space for your cavy. Our made-in-the-UK hutches have solid floors, fox-proof wire, and pair beautifully with our runs.

Some people do use a cage for living space, and that's a possibility, as long as you take into account three important factors: size, security, and flooring.

Avoid any cage or hutch wire flooring, as it can harm your guinea pig's sensitive feet. Unlike many other species, guinea pigs don't have pads on their feet. They can easily develop bumblefoot or other conditions. In addition, their toes and legs can slip through the wire and break. Solid wood makes the best flooring for a guinea pig enclosure.

Exercise Space

Speaking of runs, cavies are low maintenance pets in general, but they are active. An enclosed run can provide safe room for them to stretch their legs and entertain themselves.

A hutch and run combination can be an excellent solution for your piggie's housing.

Hutch Hygiene

Guinea pigs are clean, low maintenance pets. But that doesn't mean you don't have to help them out. Regular cleaning and hutch maintenance can help to keep your cavies healthy and happy.

Did you know that you can litter train guinea pigs? It's true, and, considering one piggie can produce 100 poops a day, keeping all of that poop in one place can seriously reduce your workload. Check out our article on litter training for more information.

Spot clean your cavies' litter box twice a day. You may have to do it more often, depending on the size of your herd.

If you're using wood, paper, or other disposable bedding, discard it when it becomes soiled. Cloth bedding is a popular choice, but you will have to wash it regularly.

Empty and clean water dishes and bottles daily, and discard any uneaten food. Once a week, wash your cavy's toys in warm water and mild, pet-safe soap.

Also, inspect your enclosure regularly for mould and mildew.

Rex Guinea Pig Diet

As with all of us, what your guinea pigs eat can have a huge effect on their health. A proper diet can prevent certain health issues, while a poor diet can cause them.

Guinea pigs are strict vegetarians. As with rabbits, a guinea pig diet should consist of mainly high quality feeding hay. In fact, hay should make up 80 percent of your guinea pigs' diet. You can supplement hay with compressed hay pellets, though these should make up no more than 10 percent of your piggies' total intake. Guinea pigs also love fresh vegetables and leafy greens.

Guinea pigs also need Vitamin C in their diet, as their bodies don't produce it naturally. The best source of Vitamin C comes from fortified guinea pig foods, as well as from cavy-safe fruits and vegetables. You can also buy Vitamin C supplements formulated just for guinea pigs.

Take care when introducing new foods to your cavy's diet, as sudden changes can upset their tummies and cause diarrhoea and other digestive issues.


In the wild, guinea pigs are constantly on the move. They have to forage for their supper, and there's no constant flow of high-quality food and treats. By contrast, pet piggies have their food brought to them, and many spend a large part of their lives in limited-space enclosures. As you can imagine, this can lead to obesity.

Like all of us, guinea pigs need exercise--Several hours per day, in fact.

The easiest way to exercise your piggies is to give them room to roam, in the form of a spacious run. You can also guinea pig-proof a room in your house for floor time. Make sure to remove all cables and cords, as well as furniture, under which your piggie might find itself trapped.

Some piggies also enjoy running in a wheel, like a hamster wheel. Just make sure that there are no gaps that can trap your cavy's toes.

Having an exercise buddy--another pig--can also help to keep your pet happy, healthy, and active.


Because of their easy care coats, Rex guineas are easier to care for than some other guinea pig breeds, particularly long haired breeds. Nonetheless, like all pets, Rexes need a bit of TLC from time to time.

Bathing Your Rex Guinea Pig

Guinea pigs are pretty good at keeping themselves clean. Even more so the short-haired Rex. Bathing can be stressful for a piggie, and should only be done when absolutely necessary.

To safely bathe your guinea pig, lay a towel in the bottom of your sink or other bathing vessel (an unusued cat's litterbox can be a good choice). Add about two inches of warm water (not too hot!)

Lower your cavy onto the towel, back feet first, allowing it to settle on the towel. Use a cup to gently wet your pig. Be careful not to wet its head. Work in a small amount of pet shampoo formulated for small animals.

Rinse and towel-dry your pig. Be mindful of drafts!

Watch the process here.

Brushing Your Rex Guinea Pig

Many cavys love to be brushed, even those with short hair, like the Rex. For a short-haired piggie, use a soft-bristled brush once or twice a week. Brush gently. This can be an enjoyable experience for both you and your Rex.

The Grease Gland

Both boars and sows have a grease gland at the base of the spine. This gland produces grease, which, if not cleaned away regularly, can cause infections.

Trim the area around the gland with scissors. Use coconut oil to loosen the buildup, then use a warm cloth to wipe away both the grease and the coconut oil.

See how it's done here:

Trimming Your Guinea Pig's Nails

Guinea pig nails grow quickly and continuously. Overgrown nails can curl under and pierce the sensitive bottoms of your piggie's feet, resulting in pain and infection. Regular nail trims can prevent this.

You'll need to trim your pet's nails every four to eight weeks, or even more often if their nails grow quickly. To do this, you'll need a set of pet nail clippers, as well as a blanket so your piggie won't slip and slide around.

This video shows three different methods for trimming your piggie's nails.

Dental Care

Guinea pigs' teeth grow continuously. As a result their teeth need special attention. Check out our article on guinea pig dental care for more information.

Rex Guinea Pigs: Health Issues

Like all guinea pigs, the Rex guinea pig is prone to certain health problems.


The ideal temperature for cavies is between 18 and 23 degrees Celsius. They don't like extremes, though they do better with colder temperatures than warmer ones. This means that if temps get high in your area, you need to protect your cavies from heatstroke.

Make sure their enclosure has plenty of shade. Provide cool pads or frozen water bottles, and make sure they have plenty of drinking water. You can even bring your cavies inside if temperatures are too high in the garden.


The smell of urine and faeces can attract flies. Flies may lay eggs on your cavies. When the eggs hatch, the maggots burrow into the skin. This is flystrike. It's painful and can become deadly fast.

Upper Respiratory Infections

Guinea pigs are prone to upper respiratory infections. These can become serious very quickly. Symptoms include sneezing, nasal discharge, and difficulty breathing.


Diarrhoea, also, can be quite serious in guinea pigs. If it's profuse and watery, contact your vet.

Dental Problems

Occasionally your cavy may break a tooth. The tooth will usually grow back in a matter of weeks. But keep an eye on the matching upper or lower tooth, as it may over-grow to compensate. If this happens, see your vet for a tooth trim.

Guinea pigs can also suffer from impacted molars. If your guinea pig stops eating or begins to drool, this also merits a trip to the vet.


Bumblefoot, or Pododermatitis, is an irritation of the feet that can progress to infection. Early symptoms include calluses on the feet, loss of fur on the feet, and reduced activity. These may progress to sores and bleeding, followed by bone and tissue infection. The earlier your vet can treat bumblefoot, the better.

When to Call the Vet

Lethargy and loss of appetite are common symptoms of many potentially serious guinea pig health issues. If your cavy's activity has noticeably decreased, or if it stops eating, it's time to call the vet sooner than later.

Symptoms of flystrike and various infections also require immediate veterinary attention.

Also contact your vet in the case of any suspected injury.

Is a Rex Guinea Pig a Good Pet For You?

If you're ready to own a guinea pig, the mellow, sociable Rex is one of the best.

Are Rex Guinea Pigs Friendly?

Rex guinea pigs are one of the friendliest breeds!

Are Rex Guinea Pigs Good Pets for Kids?

That depends.

Guinea pigs aren't good pets for small children, as children under nine years of age generally see them as toys, rather than family members. This can be a dangerous situation for a cavy.

However, for ages nine and up, the friendly, curious, easy-to-care-for Rex guinea can make an excellent pet.

Are Rex Guinea Pigs Hypoallergenic?

Technically, no. However, many people find that this breed is less likely to trigger their allergies.

Are You Ready for a Rex?

The Rex guinea pig is a friendly, easy-care, low maintenance pet. Their bristly coats are unique amongst cavies, and for many people, they can make great pets.

Do you have a Rex? Do you have any advice for our readers? We'd love to hear it!