Keeping Cavies Healthy ( I.e. Guinea Pigs ) - PETS

Here I intend to outline a few of the many different things that can befall a Cavy, and also end with the joy they can bring a household if cared for properly and a little Cavy history and list of relatives.

One more note: My Vet, a long time Cavy keeper and healer and very knowledgeable in Cavidom I might add, has approved my Instructable...That definitely makes me feel good about it.

(Pictured is one of my assistants < a silkie Teddy white but not albino piggie> helping me with this Instructable: this pretty little girl is Snuggles and she will be doing the typing / proofreading).

Step 1: Some Basics

My background is with raising these fellows for the past 18 years or so, and also quiet a bit of insight added by our Vet, who has raised them for much longer. Normally she had between 15 and 20 of them at any given time. Both our vet and my wife and I rescue these guys from the local Humane Society where they get turned in regularly.

A few generalized things to note:

They are small, so they lose body heat faster then we do. Keep the temperature within the proper range for the animal (between 65^o & 75^o if possible). Catching colds is a dangerous thing for these little guys.

FEEDING:
Another thing about being so small: what seems diluted to us may be very concentrated to them. Be careful with anything new introduced to their diet. Please avoid things that have been prepared in any way (cooked, or factory mixed in any way), or sprayed, or fertilized. They ARE vegetarians so they are accustomed to veggies and fruits. Some cavies will become picky however. Avoid "root / tuber" vegetables. Do NOT make major changes to their diet (different brands of pellets, etc.) abruptly. Mix in the brand you are changing to, a little at a time until you are giving them (within a week or more) all of the new brand. Avoid HARTZ, as it is reported that their foods set around for long periods of time, and vitamin C has a fairly SHORT shelf life. Also, because they need Vitamin C, do not use Rabbit pellets.

In addition to the hay and pellets, a variety of fresh vegetables, particularly leafy green vegetables should be offered daily. Avoid Iceberg (head lettuce) as it has very little nutritional value. Good choices include kale, spinach, turnip greens, parsley and dandelion greens, all of which provide vitamin C. Carrots, carrot tops, and just about any other fruit or vegetable can also be fed. Leafy greens should make up the bulk of the vegetable supplementation, and fruits and other vegetable can be offered in moderation.

Water: it is best to use Distilled water, or at least low mineral spring water, mostly because the concentrations of chlorine & fluorine in tap, can be harmful (and if the tap is also hard water, the non-organic minerals are not at all good either).

BEDDING / HOUSING:
Do not use cedar shavings; period. It causes many a small animal to have rashes and raw spots, and it causes severe respiratory problems in cavies. The recycled paper based product is best, although my Vet has also informed me that Aspen bedding is ok.

Also, with 2 or more cavies per cage, it is probably going to be necessary to clean the cage about twice a week (every 3 to 5 days).

Some small animals (for instance: rabbits) do not mind 'wire mesh' floors of their pens (allowing excrement to drop through and not dirty their floor); but cavies do not like them; they have VERY sensitive feet. Please give them a solid floor to stand on.

There are pluses and minus' to the arguments between aquarium or ventilated cage (wire sides only)'
On the one side is the lack of ventilation in the aquarium.
On the other side is that the drafts are cut down (cavies CAN be sensitive to a drafty environment). I haven't found one to be superior to another.

GENERAL HEALTH:
Cavies, like many small rodents, have a history. With cavies and mice and rats, the history may be somewhat spotted: that is, they may be sons and daughters from a lineage bred in labs for certain purposes. This is sad, but it means that these rodents are not always going to be simple to take care of. I personally have had 3 that developed cancer, one of them was ovarian cancer; several got kidney & bladder stones, two had horrible, yet benign cysts; and two had severe seizures (similar to epilepsy). The latest one died overnight, not having suffered anything before hand *shrug*; he was getting a bit old however (they live between 5 & 7 years on the average, and Shadow was 6 +) .

Cavies love to be held and paid attention to (despite their 'complaints' when trying to catch them), they seem to thrive on the attention. The more given, the more love will be given back. They can be and become very timid, unless handled regularly. As seen in the picture of Snuggles peering out of the cage, some just have an outgoing personality (that is Marshmallow; or Marshi in the background).

Step 2: Some Specific Rules for Cavy Health & Feeding

Be wary of what you read in books on Cavy care. So many of them are either outdated or are written by Cavy Pellet Manufacturers & proclaim it a MUST to use pellets as the mainstay to feed them. While a good pellet (and few there are that are really good) will help balance the diet, cavies like a variety. Feeding only Guinea Pig pellets will not give them the balance they need; although there is one which is called Cavy Cuisine which comes very close. It is the only one recommended by my vet (no, I don't work for them nor do I have stock in the company :-P ). Also beware of SOME "breeder's" advice. Some of them raise and breed in bulk and show them for prizes, but do not have the welfare of the poor animal in mind. More information on Cavy Care from Oxbow

A word about bowls. There are 2 types sold for Cavies and other small animals. While, healthwise it doesn't matter too much which kind you get (plastic or porcelain), food waste will be cut down if you get the heavier porcelain bowls. Some larger cavies will still be able to upend the bowl towards themselves to make it easier to get at the food (but this spills food out that, if it becomes too soiled, they will refuse to eat); but it is harder for most to move the heavier bowl. The lightweight plastic ones, they learn fairly quickly how to "dump n chomp" from :-)

Cavies LOVE hay, but be careful again. Alfalfa hay is VERY rich in calcium and WILL give your piggies bladder stones. Use Timothy hay instead (Cavy Cuisine has Timothy hay in the pellets, but they seem to love having more hay to chew on and lie in). This goes for pellets also, make sure they are Timothy hay based and not Alfalfa based because of the bladder stones. It is a must for their digestive health !

It can be hard to get enough vitamin C to these little guys without hurting their teeth. Much of the food really rich in Vitamin C may be rejected by them (parsley for instance, which may be too strong for some; although mine tear it out of my hand) or oranges (avoid very high acid fruits like lemons and limes, which have more sugar in them then oranges anyway).

My wife has gotten liquid vitamin C from the pharmacist, and uses a small syringe (no needle of course) to help 'get it into their mouths, past the front teeth anyways. Once they realize you are not trying to poison them, they will take it readily enough (two of ours consistently grab the syringe away from my wife trying to get more out of it :-).

What can we introduce to our piggies as food ? Nearly anything called a fruit or vegetable: cavies are vegetarians. Piggies like their food particularly clean.
Mine like oranges, bananas, grapes, cherries, peaches, apples, etc. in the fruit family, and in the veggie family, again nearly anything EXCEPT potatoes (they are not good to eat raw, and nothing cooked should be given your piggies), onions, leeks, cucumbers, and nightshades like peppers (even sweet ones) should all probably be avoided. A little tomato is ok, especially low acid 'maters (actually, whatever you introduce along these lines, make it only a little). I would stay away from lettuce also, it is mostly fiber and water, and provides little nutrition. This is one of the few "green leafies" that may give your little guy or gal loose bowels.
Spinach in moderation is ok, in fact, the green leafies are what they love the most, as it is closest to what they eat naturally anyway. The leaf vegetables highest in Vit. C. BUT lowest in calcium are the best. Avoid those with high mineral content: not too much spinach, and no or almost no alfalfa, etc. Again, some things are better tolerated by some piggies; they have their little personalities. We had some that would not take any spinach (not a strong flavor) but loved parsley (???) which has a rather strong flavor to it. Some just love dandelion greens (we buy organic here, as what is in our yard may have been exposed to the pollutants in the air, automobiles etc, and is probably not very healthy), and some lean more towards collards etc.

Make sure the cavy has PLENTY of clean water. A bowl is not good for this, they tend to get the water dirty fairly quickly, and then will not drink from it. Find a decent sized water bottle that will hang from the side of the cage. Try to give your piggie "room temperature water (not too cold nor too hot). Distilled would be best, low mineral spring water is next best. Tap being the worst.

What appears to be a little quirky, that one piggie will sometimes eat the droppings from another piggie, is actually a survival technique. Any unused Vitamin C or other nutrients from one, can be used by another (for example, since Vitamin C is water soluble, any unused will pass on into the waste). So, don't become alarmed when you see this, it is natural for them.

A word about introducing a new piggie into a group or to another lonely piggie:
The one or more that have "established" a territory in the pen/cage will be a bit aggressive if you just dump a new one into the cage.
There are two good methods you can take towards making the introduction more smooth:
#1: you can section off another unused cage or area on the floor, and introduce them in that neutral territory. Let them get acquainted (which may take awhile) before putting them into a cage (it might be best, while they get to know each other, to clean the cage they will be using),
#2: the other way is if you have some / one in one cage and some / one in another, and you want to "get them together"; simply switch the cages they are in (piggies A in cage A, moved to Cage B, and piggies B in cage B moved to cage A). They will get used to each other's smell this way before the big meeting :-)

Step 3: Specific Health Concerns

Bladder stones: Calcium is the bane here. Foods rich in calcium are to be avoided ( Alfalfa, and Alfalfa based pellets, especially). I can't emphasize that enough.

"Barbering" also called clunking results in hair loss. This vice occurs when guinea pigs habitually chew on the hair coats of cage-partner guinea pigs that are lower in the social "pecking order." Younger guinea pigs in particular, can lose substantial amounts of hair as a result of this activity. It normally appears in a V shape on the back (the hair loss). Hair can also be lost because of fungal disease and external parasite infestations.

Concerning parasites -
Mange: A mite similar to the scabies mite of people causes serious infestations in pet guinea pigs. Mites are microscopic, spider-like organisms that live within the outer layers of the skin. They usually cause intense scratching and significant hair loss. Some cases without scratching have been reported. Some guinea pigs are so miserable because of the infestation that their constant scratching produces serious wounds.

Lice and mites are the most common external parasites of guinea pigs. Lice are tiny, wingless, flattened insects that live within the hair coat Both the adults and their eggs are found attached to individual hairs.
Guinea pigs may be parasitized by 2 types of biting lice. Both abrade the skin surface and feed off of body fluids that exude through the very superficial wounds they create.

Light infestations usually go unnoticed. Heavy infestations are usually accompanied with excessive Itching, scratching and some hair loss. Scabs may also be evident on and around the ears.
A veterinarian can confirm the diagnosis by direct examination of the hair coat. Direct examination is usually all that is necessary, though use of a magnifying lens or microscope is very helpful. The veterinarian will usually prescribe an insecticidal shampoo to treat affected guinea pigs. The most mild treatment and a very effective one too, is using Lyme Dip. It smells exactly like sulfur (rotten eggs, if you aren't familiar with sulfur), but is EXTREMELY mild and can be left on the coat.
Recommendation: remove the piggies from the cage, and after cleaning the cage, spray the Lyme Dip all over the cage to get the little buggers from there first. Then take and spray/dip the piggie as per the instructions. Be forewarned, your piggy will protest ! He/she will sound like you are torturing them (like the squeals you get when cutting their nails. ;-)
Rinsing and a thorough patting dry is recommended as the dip does smell very bad, and you don't want your piggie to catch cold.

Lice can be transmitted by direct and intimate contact between infested and uninfested guinea pigs. Therefore, pet guinea pigs are very unlikely to harbor these parasites unless they are recent acquisitions that were previously in contact with louse-infested guinea pigs. Established pet guinea pigs could also be infested by being placed in close contact with new, infested guinea pigs or from shavings / or hay. Guinea pig lice do not parasitize people.

Pneumonia is one of the most common bacterial diseases of pet guinea pigs. A number of potential disease-causing bacteria may inhabit the respiratory tracts of otherwise healthy guinea pigs. Stress (transporting, frequent environmental changes, etc), inadequate diet, and improper home care often predispose a pet guinea pig to respiratory infection. If you have a cough, avoid being around your piggie as they can catch some of the respiratory maladies you have.
Signs of pneumonia may include labored or rapid breathing, discharge from eyes and nostrils, lethargy and inappetence. Some animals show no signs at all before dying suddenly.

lung (allergy-latex, dust {especially wood shaving dust NEVER USE CEDAR}, anaphylaxis, asthma, inhalation-leather conditioner, toluene) . Symptoms can be as mild as discharge from the nose (normally noted on the piggie's sleeves (ankles of the front legs), where you will be able to observe him/her wiping their noses with frequently.

Walking difficulties: Serious (sometimes crippling) infections of the footpads are common among pet guinea pigs housed on wire. The other major predisposing actor is fecal soiling of wire-bottomed enclosures. The front feet of overweight animals are especially vulnerable to this condition. So, do not use wire bottomed cages. Signs include swelling of the feet, lameness, reluctance to move, and inappetence. The flooring of the enclosure must be changed and overall sanitation must be improved. A veterinarian must be consulted regarding treatment of the affected feet.

Scurvy, which is characterized by inappetence, swollen, painful joints and ribs, reluctance to move, poor bone and teeth development, and spontaneous bleeding from the gums and into muscle. Of course, this is from a lack of Vit. C. Oranges, Kale, Spinach, and many other greens and fruits can supply enough, but if the piggie is a little food picky, your vet can recommend a liquid brand and dosage that will meet your piggie's needs.

Cancer was a relatively rare problem of guinea pigs. As with most animals, it is most likely to affect older guinea pigs. Most tumors are benign and involve the skin and respiratory tract lining. Cancer may also affect the reproductive tract, mammary glands (breasts) and blood (leukemia).
As the gene pool narrows however, it has become more frequently observed in Guinea Pigs.

Cavies are especially susceptible to heat stroke, particularly those that are overweight and/or heavily furred. Environmental temperatures above 85^o F, high humidity (above 70^%), inadequate shade and ventilation, crowding and stress are additional predisposing factors. Signs of heat stroke include panting, slobbering, weakness, refusal to move about, delirium, convulsions and eventually death. Heat stroke is treatable if recognized relatively early. Heat-stressed guinea pigs should be immediately sprayed with or bathed in cool water, cool damp compresses can be used if there are no drafts . Once this first-aid is undertaken, a veterinarian should be contacted immediately.

Teeth overgrowth: A common problem of guinea pigs (especially those over 3 years old) results when the upper and lower premolar teeth (the most forward cheek teeth) meet improperly while chewing. In time, this problem results in abnormal wear of these teeth. This in turn causes entrapment of and continual injury to the tongue; sometimes preventing the mouth from being closed. Affected animals try to eat but cannot chew and swallow food. Drooling results in a continually moist mouth and chin. Weight loss is often dramatic. A veterinarian must be consulted as soon as possible if this condition is suspected. The diagnosis is confirmed upon direct visual examination of the mouth. Correction of the problem involves aggressive trimming or filing of the overgrown teeth. This is a difficult procedure because of the guinea pig's extremely small mouth opening (and their tendency to push their tongue into the way).

As mentioned earlier, there is a little controversy about cages. While some claim that all drafts can be "bad" for the Cavy (thus promoting the "aquariums" as cages), while others claim that too much C0₂ will make the Cavy ill, and they need the fresh air, and promote "wire" cages (special note: not wire "bottomed" cages, just the sides/top)).
I have had cavies in both (actually I have a male in a make-shift aquarium and 3 females and a neutered male in a "cage" and all seem to be doing just fine). Just make sure you have a solid bottom.
A trick to make cleanup a little easier, if you get a lot of "paper bags" from the grocer, cut/tear them up to the size of the bottom of the cage, and then put your "bedding" down on that. 99% of the cleanup will be carefully lifting up the paper and dumping the whole mess into the trash. They may find the paper and chew on it, but it is relatively harmless, not having coloring or much ink in it.

This brings us to another point: they do like to chew, which is fortunate because, unlike you and me and many other animals, their teeth do not ever stop growing. If they didn't have something hard (like a chemical free wood block, etc.) to chew on, their teeth would overgrow and they would "starve" from not being able to close their mouths and chew.

Guinea pigs are very shy creatures, and it sometimes takes a long time to "warm up" to being picked up (you see, they HATE to not have something under their feet). But being held and stroked is probably one of the most important things that can be done with them. The This is especially true if you only have one.
Second picture below, shows one proper way to hold one, always with their feet firmly supported (by my wife). Younger persons should use both hands.
They are social animals and really NEED a partner (unless you want a lot more then two, pair up males with males and females with females or get one of the pair neutered ). They enjoy exploring too, but only after 2 things are made sure: #1, there is nothing nearby that they can get into (holes in the floor, walls, behind sinks etc) & #2: nothing they can get that would poison or harm them in any way. Please, not on the basement floor, it will always be too cold for them, even in the Summer (approximate temp. 54^o F or 12^o C). If you can make an enclosure for them to run about in, they will love being out, but it will take them quite awhile to start looking about, although some piggies have a naturally curious nature and will go as soon as they get set down.
Chew toys should not include metal or plastic or anything "animal" like rawhide. Cavies are vegetarians and can not tolerate anything more complex (animal-wise) than yogurt (sometimes used to help a piggie eat when being spoon fed and nursed back to health; it rebuilds the flora of the digestive tract).
We have had NO success with getting a cavy to run about in one of those large floor balls, that hamsters, gerbils and the like enjoy. They have big ones for Cavies but they normally just sit there waiting for you to put them back in their cages where it is safe LOL

A recommendation: It is always good to get into the habit of weighing your cavy. Once you have an average weight, any "quick changes of a half pound or more, can be considered serious.
Also, if your cavy stops eating for more than 4-6 hours, it is time to get some help. The teeth may be overgrown, or something else very serious maybe going on, but the little fellow hasn't a lot of reserves, so it is good to get them to the vet/emergency clinic fairly quickly.
Loose non-firm stools are another problem. anything from getting too much of a certain "treat" to viral infection can cause this. It's danger lies in dehydrating the little guy. It can occur rather quickly.

One of my biggest pet peeves is that there is so much misinformation out there in books, and on the web about the care of these little guys.
Feeding them pellets everyday and only pellets is like being condemned to eating oatmeal for every meal for the rest of our lives. ... not fun.

Step 4: Types of Guinea Pigs / Cavies

This is by NO means a comprehensive list:

If you like the "normal average guinea pig", the American shorthair is one of the most common.

The Abyssinian is really neat looking, with their whorls all over, but they take a little extra care to keep the coat clean.

Speaking of extra effort, the Peruvian is much more work yet. With the longer hair, combing, deknotting, and cleaning are the regular order of business.

The Silkie or Sheltie is another "high maintenance" Cavy, unlike the Peruvian, it's long hair does not "part naturally" down the back.

There are several different versions of the Crested cavy, with it's whorl or crest on the forehead. Normally a short haired piggie, and not hard to take care of.

The Texel: This uncommon guinea pig has a very distinctive long curly coat. The Texel guinea pig is another very high-maintenance pet.

The Coronet Guinea Pig is also long-haired, but has a single rosette ("coronet") in the center of the forehead. Like other long haired guinea pigs, Coronets need lots of grooming.

The Teddy comes in 2 "styles": The regular Teddy has a short, wiry, dense coat. The hairs, and even the whiskers, are kinked. The coat is resilient, meaning it returns to its original position after being disturbed. The body of the Teddy is similar to the American in length, and it has a Roman nose.

The Teddy Satin has the same general appearance as the Teddy, but the coat has a glossy sheen. The Cavy shown in the INTRO & in Step 1 is a Teddy.

Hairless Guinea Pigs: There are actually two varieties of hairless guinea pigs. The Skinny pig, which does actually have a bit of hair, and the Baldwin guinea pig. There is some controversy about the introduction of these guinea pigs to the pet industry. They were originally bred for laboratory research, and concerns about their immune system function and overall hardiness have been raised. Others say that through careful breeding, it is possible to produce hairless guinea pigs that are hardier than their lab-bred ancestors. And while some people find their unique appearance unappealing, others find them quite irresistible. Their care is much like that of other guinea pigs. However, lacking a coat they are a bit more sensitive to temperature extremes and must be protected from drafts as well as direct sunlight.

Step 5: Sadness....and Gladness

Sadly, these guys, as mentioned before only live about 5-7 years (about twice as long as they would in the wild) and sometimes come down with many "inbred" diseases.

Sometimes it is impossible or hard, at least, to know what was the cause of their demise (who wants to have their close family member butchered {i.e. autopsied} just to find out?).

We try to make them as comfortable as possible and let them know they are not alone as they fade (I held Honey, the male cavy in the picture, until he took his last breath; he seemed to have waited until we got home to be with family before he closed his eyes and fell asleep.

On the BRIGHT side, they are lovable, interesting pets that with the proper care and handling soon endear themselves into a loving position in our family and our hearts. They are not as dumb as some people think either. Ours "know" the sound of my car pulling up outside when I get home at night, and start rustling about, with at least one piggie "sounding the alarm" which any cavy owner recognizes: weeep weeeeeeeep !

I nearly forgot. I should mention "toys". Guinea pigs are gnawers as mentioned before, and so anything you put in the cage with them, they WILL try to eat or chew. Wood objects (untreated pet safe items) are best. They help keep the teeth worn down and the little guys n gals will just love it. We have an "underpass" (rounded section of the bark and about 3 inches of the wood) gotten at a pet store. This way they can hide (something they like to do now an then too) and chew when they feel like it. It is quite sturdy and has lasted over 2 years for us now.

Step 6: Some Information, Background and Relatives...

CAVY {cavy} ,
name for 14 species of South American rodents of the family Caviidae,
including the domestic guinea pig.

Besides size difference, hamsters, mice, etc. are somewhat omnivores (I witnessed a hamster I had catch and eat a moth) and their prepared pellets contain meat proteins many times, as well as grain/veggies. Their young, are born eyes closed and hairless/helpless.

Anyone that has bred guinea pigs has come upon the new born cavies as little miniatures of the adults. Eyes open, and fully furred. We even had one (Daddy's Cinnemon Girl) follow her dad around the first day and tried some pellets, just hours after birth. Guinea pigs, btw are vegetarians once they are weaned. They are up and about minutes after momma cleans them off.

Here is a little about the wild ones (sorry if my notes look a bit jumbled):

Order: Rodentia (Rodents)
Sub order: Caviomorpha* (Guinea pig like rodents)
Caviomorph heads are large, the bodies plump, the legs slender and the tails short. The most distinctive characteristic of these animals is the formation of the jaws and the massater muscles. One branch of the massater extends forward through a very large foramen in the zygomatic arch to attach to the side of the rostrum. The other end of the massater attaches to a characteristic flange on the lower jaw.

FAMILY: Caviidae
SUBfamily: Caviinae
Caviidae is first distinguished geologically during the Miocene period. Today caviidae, consists of three genera
A close relative of the cavy, the apurea, is found in South America at altitudes up to 13,000 feet. It is likely that the original wild cavies were found at those same altitudes.

The family is characterized by various traits such as dental formula (i1/1 c0/0 p1/1 m3/3 = 20 teeth) and digits (four on fore foot; three on hind foot). In addition to guinea pigs (Cavia), other members of this family are Patagonian cavies or maras (Dolichotis) and rock cavies, or mocos (Kerodon). All species of this family have been used as food by humans, though only Cavia is known to have been domesticated.

The rock cavy (or moko) is the Olympic champion of the cavy world. This athletic specimen can jump several yards, move quickly and easily over rocky terrain and cliffs, and even climb trees for a leafy snack.
The Berlin Zoo once had a rock cavy that climbed the smooth glass and concrete walls of its enclosure. They prefer to live under boulders and in crevices of mountain areas in southern Brazil.

The false paca (or long tailed paca) has a rough coat, a large mustache, and a long tail. It is comfortable sitting upright. Rare and seldom seen, the false paca may be facing extinction. Such a shame to lose this unique and precious member of the family.

The nutria (or coypu) is a marsh-loving animal that digs its burrows in the sloping banks of streams and lakes. Originally from South America, the nutria is now also found along rivers and streams in southern Canada and scattered parts of the U.S. Like the capybara, the nutria has webbed feet, ears that close shut under water, and is a terrific swimmer.

Adults are about 3 feet long (including a round scaly tail) and weigh 10-20 pounds. These guys look like a cross between a guinea pig and a beaver.

The mara is a big cousin of the cavy. Adults are 30" long and weigh 20-35 pounds. This animal is sometimes incorrectly called a pampas hare, due to its resemblance to a rabbit. The mara can run exceptionally fast, jumps up to 6 feet, and digs deep broad burrows. It lives in dry grasslands and thickets.
> Also:
Cavia anolaimae
> Cavia aperea - - Brazilian Guinea pig: widespread east of the Andes
> Cavia fulgida - - Shiny Guinea pig: eastern Brazil
> Cavia guianae
> Cavia intermedia - - Intermediate Guinea pig: Moleques do Sul islands, Santa Catarina,
Brazil, first described in 1999
> Cavia magna - - Greater Guinea pig: Uruguay, south-east Brazil
> Cavia nana
> Cavia porcellus - - Domestic Guinea pig: wild ancestor unknown found in Brazil
> Cavia tschudii - - Montane Guinea pig: Peru south to northern Chile and north-west Argentina
> Cavy Boliviensis - the high Andes
> Cavy Cutleri - Peru
Kerodon rupestris is considered one of the wild ancestors of the modern guinea pig.

Unlike many animals the boar Guinea Pig is kind to his newborn children. He shows them and his wife affection with a low, contented purr from his throat and often helps the mother take care of her children. When going on a walk or stroll, the new family of guinea pigs will walk with one parent in front and the other behind so that nobody gets lost.

The golden agouti (black hair tipped with red) or cinnamon agouti (chocolate hair tipped with red) colored American cavy, with it's short smooth coat, would most resemble the wild cavy.
The animal called an Agouti, is similar in structure but is not a member of the cavy family. http://www.wellingtonzoo.com/animals/anima...als/agouti.html
http://www.honoluluzoo.org/agouti.htm
http://en.wikipedia.org/wiki/Agouti

Technical stuff: According to most biologists, guinea pigs are categorized as follows: class Mammalia; order Rodentia; suborder Hystricognathi; family Caviidae; genus Cavia; species Cavia porcellus. Some researchers choose to elevate the two suborders within Rodentia to the status of order; under this scheme, "true" rodents (squirrels, rats, mice, etc.) are distinguished from so-called "hystricognath" rodents (porcupines, chinchillas, capybaras, mole rats, guinea pigs, etc.). The distinction is primarily a semantic one, since both classification schemes acknowledge two major lineages among the animals known commonly as rodents. In South America, wild or feral cavies inhabit rocky areas, savannas, forest edges, and swamps from Columbia and Venezuela southward to Brazil and northern Argentina. They live in groups of up to about 10 individuals and inhabit burrows that are dug by themselves or by other animals. They are most active at night, when they forage for a wide variety of plant materials. In the wild, guinea pigs mate throughout the year. Females typically give birth twice a year to litters of 1-4 pups. Adults reach a top weight of about 700 grams. The pelage of wild forms is generally courser and longer than domestic short-hair breeds, though it is mostly shorter and straighter than the various long-hair and other fancy breeds. The color is much less variable in wild populations than among domestic cavies. It tends to be uniformly grayish or brownish and may be considered most similar in appearance to some of the solid "agouti" varieties. (See my pic of Jasmine in Step 2 for an example of one of my own, as she is Agouti colored).

One final thing, I was informed of a children's book concerning Guinea Pigs that might be worth a look. It can be gotten @ Teddy & Pip's a Tale of Two Guinea Pigs site