---
title: Guinea-Pig — Care & Reference Manual
author: codebuddy
type: manual
llm_refined: true
refined_by: kimi
manual_v2: true
date: 2026-08-04
source_topics: exotic_pet_profile_guinea_pig, exotic_pet_food_nrc_standard_map, exotic_nutrition_guinea_pig_ratio, exotic_nutrition_guineapig_feeding, exotic_nutrition_guinea_pig, exotic_nutrition_guinea_pig_vitamin_c, exotic_pet_nutrition_guinea-pig_safe_greens, exotic_husbandry_guinea_pig_diet, exotic_husbandry_guinea_pig_housing, exotic_life_stage_guinea_pig, exotic_behavior_guinea_pig, exotic_enrichment_guinea_pig, exotic_grooming_guinea_pig, exotic_breeding_guinea_pig, exotic_gp_cystic_ovarian_disease, exotic_health_guineapig_emergency, exotic_guinea_pig_urolithiasis, exotic_guinea_pig_vitamin_c, exotic_guinea_pig_pododermatitis, exotic_tox_guinea_pig_penicillin, exotic_tox_guineapig_foods, exotic_tox_guinea_pig_penicillin_syndromes, exotic_pet_legality_crosswalk_guinea-pig, evidence_exotic_guinea_pig_clinical, evidence_exotic_guinea_pig_husbandry_health, evidence_exotic_guinea_pig_toxicology, evidence_exotic_guinea_pig_nutrition
source_hash: ed75f21003730049
draft: false
---

# Guinea-Pig — Care & Reference Manual

*LLM-refined manual (v2 pipeline, kimi, 2026-08-04; docs/MANUAL_V2_DESIGN.md).* This manual assembles the verified fact blocks in Pet Data Station that mention *guinea-pig*, organised along a pet owner's journey. Every quoted fact is reproduced **verbatim** from its cited first-hand source (`[n]` superscripts; see References, each tagged with a computed trust grade per docs/topic_grading_guide.md) and is independently checkable. Guide sections (checklists, red-flag box) are orientation prose in which **every factual sentence carries its own `[n]`**; derived-summary blocks from non-Open-Access sources keep their *Paraphrased derived summary* mark. Mis-sectioned, duplicate, off-topic and image-residue fragments were removed by the v2 builder (build-gate enforced).

## Contents

1. [Species Profile](#species-profile)
2. [Life-Stage Care](#life-stage-care)
3. [Is this pet right for you?](#is-this-pet-right-for-you)
4. [Daily & Weekly Care Checklist](#daily-weekly-care-checklist)
5. [Nutrition](#nutrition)
6. [Husbandry](#husbandry)
7. [Behavior & Training](#behavior-training)
8. [Enrichment & Exercise](#enrichment-exercise)
9. [When to call a vet NOW](#when-to-call-a-vet-now)
10. [Health & Disease](#health-disease)
11. [Toxicology & Hazards](#toxicology-hazards)
12. [Grooming](#grooming)
13. [Breeding & Neutering](#breeding-neutering)
14. [Regulations & Legality](#regulations-legality)
15. [Appendix A — Commercial Food & Regulatory Notes](#appendix-a-commercial-food-regulatory-notes)
16. [Appendix B — Research Evidence](#appendix-b-research-evidence)

## Species Profile

The profile below records this species' taxonomy, natural origin and lifespan as documented in the cited reference.

### Guinea pig (Cavia porcellus) — species profile (taxonomy, geographic range, habitat, physical description, behavior, wild diet, reproduction, lifespan)

> Guinea pigs, also known as cavies, no longer exist in the wild. [1]
> Their domestication began around 5,000 B.C., and because of their popularity as pets and food, they are now globally distributed. [1]
> They are indigenous to South America, with fossil records extending as far back as 9,000 B.C. [1]
> Scientists believe that guinea pigs were domesticated from a now extinct wild species that lived in northern and western South America. [1]
> Guinea pigs no longer exist in their wild, native, grassland habitat. [1]
> Prior to their extinction, however, they were extremely adaptable and could survive in a variety of environments. [1]
> For example, they can live in a broad range of elevations, from sea level to 4,000 m. [1]
> Although studies have shown that they cannot survive in extreme hot or cold, guinea pigs can tolerate a large range of temperatures, from 22˚C in the daytime to -7˚C at night. [1]
> Guinea pigs are tailless rodents that weigh between 700 g and 1100 g, with males being larger than females. [1]
> They have small, compact, cynlindrically shaped bodies, ranging from 20.3 cm to 25.4 cm in length. [1]
> They have small petal-shaped ears that are laterally positioned at the apex of the head. [1]
> Their eyes are laterally positioned mid-way down the snout, between the ears and nose. [1]
> Guinea pigs are gregarious and prefer close contact with other conspecifics. [1]
> As a result, males are often separated when females are present. [1]
> Guinea pigs are strict herbivores and depend on humans for food. [1]
> Domestic guinea pigs are often fed lettuce, cabbage, and various types of grasses and fruit. [1]
> In some cases, barley and "Timothy hay", a wide-spread perennial grass, are grown especially for consumption by domesticated mammalian herbivores such as guinea pigs. [1]
> In more developed areas, they are often fed manufactured feed pellets. [1]
> Both monogamous and polygamous systems occur, depending on how animals are housed. [1]
> Guinea pigs are host to many different parasite species, including mites, ticks, sucking lice, chewing lice, nematodes, and flukes. [1]
> The most common among these are mites and lice, of which only 3 species are capable of breeding and reproducing on domesticated guinea pigs ( Trixacarus caviae, Gliricola porcelli, and Chirodiscoides caviae ). [1]
> The most prevalent of these are mange mites ( T. caviae ), which burrow under the skin. [1]
> Due to their domestication, guinea pigs are not subject to natural predation. [1]
> Guinea pigs are extinct in the wild and only live in captivity. [1]
> These include the American, American satin, Abyssinian, Abyssinian satin, Peruvian, Peruvian satin, silkie, silkie satin, teddy, teddy satin, texel, coronet and the white crested. [1]

## Life-Stage Care

Young, adult and senior care for this species, drawn from first-hand care pages and veterinary references.

> Guinea pigs can live up to 14 years in captivity, but have an average lifespan of 8 years. [1]

## Is this pet right for you?


- **They need a friend:** guinea pigs are very social and need to interact with other friendly guinea pigs; keep a guinea pig with at least one other friendly guinea pig unless a vet or behaviourist advises otherwise. [2]
- **They are herd animals:** guinea pigs are gregarious and prefer close contact with other conspecifics. [1]
- **They are herbivores that need you for food:** guinea pigs are strict herbivores and depend on humans for food. [1]
- **They are small and easily hurt:** guinea pigs weigh 700–1100 g and are easily injured outside the cage because of their small size. [1] [3]
- **They are most active at dawn and dusk:** guinea pigs are active during dusk and dawn (crepuscular). [1]
- **They need daily care:** plan for daily out-of-cage time, daily dietary vitamin C, and regular grooming and nail trimming. [3] [4]


## Daily & Weekly Care Checklist


Every day:

- Good-quality hay should make up the majority of the diet and be available at all times; fresh grass as often as possible, ideally every day. [4]
- A fresh portion of grass-based guinea-pig pellets daily (following the manufacturer's instructions) to supply essential vitamin C; give a fresh portion each day and use by the best-before date. [4]
- Fresh vegetables and herbs that are good vitamin C sources, fed daily — for example parsley, celery, peppers, cucumber, gem lettuce and romaine lettuce. [4]
- Fresh clean drinking water continuously available and checked twice daily; without water guinea pigs become seriously ill. [4]
- Provide more hiding places than animals (e.g. three guinea pigs need at least four hides). [5]
- Daily supervised out-of-cage time in a guinea-pig-proofed area free of cords and other chew hazards. [3]
- Monitor the amount eaten and drunk and the droppings daily. [4]

Every week:

- Groom and trim nails regularly; start nail clipping when guinea pigs are young so they become accustomed to it. [3]
- Long-haired breeds need regular brushing to prevent matting. [3]
- Do not use exercise wheels, which can injure guinea pigs. [3]


## Nutrition


Base the diet on grass hay available at all times, a daily fresh portion of grass-based pellets for vitamin C, and daily vegetables and herbs; guinea pigs cannot make their own vitamin C and need it supplied at every life stage. [4] [6]


The quotes below summarise this species' dietary requirements and nutrition-related disease risks, drawn from professional veterinary references.

### Guinea pig diet structure — hay as the staple, daily fresh pellets, daily vegetables (RSPCA-derived)

*All lines in this block are paraphrased derived summaries — non-Open-Access source.*

> Hay is the dietary staple: good-quality hay must be constantly available, and fresh grass should be given as often as possible, ideally every day. [4]
> A fresh daily portion of grass-based guinea-pig pellets (quantity per the manufacturer's instructions) supplies essential vitamin C, which degrades over time and faster with air exposure — so a fresh portion must be given each day rather than just topping up the bowl. [4]
> Broccoli, spinach, kale, small pieces of carrot and a quarter of an apple are treats only — small amounts a few times a week, because of their high sugar or calcium content. [4]
> Lawnmower clippings must never be fed — they upset guinea pigs' digestive systems and make them ill. [4]
> Fresh clean drinking water must be continuously available and checked twice daily; without water guinea pigs become seriously ill. [4]

### Guinea pig diet — feeding ratio, safe greens and foods to avoid

*All lines in this block are paraphrased derived summaries — non-Open-Access source.*

> Good-quality hay should make up the majority of a guinea pig's diet and should be available at all times; fresh grass should be provided as often as possible, ideally every day. [4]
> A fresh portion of grass-based guinea-pig pellets should be available daily (following the manufacturer's instructions) to provide essential Vitamin C; Vitamin C is destroyed over time and more quickly with air exposure, so a fresh portion must be given each day and pellets eaten by their best-before date. [4]
> Fresh vegetables and herbs are excellent sources of vitamin C and can be fed daily (examples: parsley, celery, peppers, cucumber, gem lettuce, romaine lettuce). [4]
> Guinea pigs are natural grazers and produce two dropping types (hard dry pellets and softer moist pellets they eat directly from their bottom), which are an essential part of their diet. [4]
> Avoid sudden changes in diet; introduce new foods gradually and adjust feeding quantities to prevent underweight or overweight. [4]

### Guinea pig nutrition — dietary vitamin C requirement

*All lines in this block are paraphrased derived summaries — non-Open-Access source.*

> Guinea pigs are obligate herbivore hindgut fermenters built for a high-fiber, low-nutrient, poorly digestible diet. [5]
> Adults need high-quality grass-based hay, plus grass-based species pellets and produce. [5]
> Growing guinea pigs need leafy greens and low-sugar fruit such as bell peppers, cucumbers, and tomatoes. [5]
> Make all diet changes gradually. [5]
> They need a steady vitamin C source: about 10–25 mg/kg/day for adults and 30 mg/kg or more for growing, pregnant, lactating, or ill individuals. [5]
> Many commercial pellets use a stabilized form of vitamin C that resists breakdown by heat and light. [5]

### Guinea pig nutrition — dietary vitamin C requirement (no endogenous synthesis)

*All lines in this block are paraphrased derived summaries — non-Open-Access source.*

> Guinea pigs cannot make their own vitamin C and need it supplied in the diet at every life stage. [6]

### Guinea pig safe greens & vegetables — grazing herbivore; daily vit-C veg, treat veg, foods to avoid

*All lines in this block are paraphrased derived summaries — non-Open-Access source.*

> Guinea pigs are natural grazers; good-quality hay and grass should make up the majority of the diet and be available at all times, with grass-based pellets given daily to supply vitamin C, which they cannot synthesise. [4]
> Safe greens include fresh vegetables and herbs fed daily as vitamin C sources — parsley, celery, peppers, cucumber, gem lettuce and romaine lettuce. [4]
> Treat vegetables given in small amounts a few times weekly (because of sugar or calcium content) include broccoli, spinach, kale, small pieces of carrot and a quarter of an apple. [4]

> Feed pellets contain compressed plant material (barley or alfalfa) and many of the vitamins and minerals (e.g., vitamin C) guinea pigs require to stay healthy. [1]
> *[Paraphrased derived summary — non-Open-Access source.]* All guinea pigs need vitamin C in the diet; they cannot make it themselves because their L-gulonolactone oxidase gene is mutated, and deficiency damages type IV collagen, laminin, and elastin. [6]
> *[Paraphrased derived summary — non-Open-Access source.]* Overgrown or misaligned teeth are usually linked to poor nutrition (e.g., lack of vitamin C or fibre, or other husbandry gaps), though trauma and genetics can also play a role. [6]
> *[Paraphrased derived summary — non-Open-Access source.]* Guinea pigs lack the enzyme L-gulonolactone oxidase, which is needed to synthesise ascorbic acid (vitamin C) from glucose. [7]
> *[Paraphrased derived summary — non-Open-Access source.]* Their daily vitamin C requirement is typically 10–25 mg/kg of body weight. [7]
> *[Paraphrased derived summary — non-Open-Access source.]* Adding vitamin C to drinking water is not advised: the water must be changed often and the vitamin can taint the flavour, reducing how much the animal drinks. [7]

## Husbandry


Use a solid-floor enclosure to avoid pododermatitis, with bedding of recycled paper products or fleece (avoid sawdust, a respiratory hazard, and cat litter, which is indigestible), kept at about 18–24°C out of direct sunlight and drafts. [5] [3]


Housing, environment and daily-care essentials for this species.

### Guinea pig housing — flooring/bedding linked to pododermatitis

*All lines in this block are paraphrased derived summaries — non-Open-Access source.*

> Pododermatitis (footpad sores) is common in guinea pigs and has several causes; pressure from unsuitable flooring such as wire, or from abrasive or soiled bedding, can trigger it. [6]
> Guinea pigs may fracture and misalign their incisors by pulling on cage bars or wires, distorting the teeth as they regrow. [6]

> *[Paraphrased derived summary — non-Open-Access source.]* Use a solid-floor enclosure to avoid pododermatitis and foot or limb injury. [5]
> *[Paraphrased derived summary — non-Open-Access source.]* Bedding may be recycled paper products, fleece, or other fiber- and string-free material. [5]
> *[Paraphrased derived summary — non-Open-Access source.]* Provide more hiding spots than animals (e.g., three guinea pigs need at least four hides). [5]
> *[Paraphrased derived summary — non-Open-Access source.]* Many commercial guinea pig cages are too small, especially for more than one animal. [3]
> *[Paraphrased derived summary — non-Open-Access source.]* Minimum cage space: at least 7 sq ft (about 42 x 24 in, or 106 x 61 cm) for one guinea pig; add 2–4 sq ft per additional animal; height about 18 in (46 cm); cages may be hard plastic, metal or wire. [3]
> *[Paraphrased derived summary — non-Open-Access source.]* Place the cage where the temperature is 65–75°F (about 18–24°C), out of direct sunlight and drafts. [3]
> *[Paraphrased derived summary — non-Open-Access source.]* Arrange the cage so the guinea pig moves between sleeping, eating and drinking areas. [3]
> *[Paraphrased derived summary — non-Open-Access source.]* Add a second level with a solid ramp or a small barrier to encourage movement. [3]
> *[Paraphrased derived summary — non-Open-Access source.]* Guinea pigs are easily injured outside the cage because of their small size. [3]
> *[Paraphrased derived summary — non-Open-Access source.]* Before handling, have the cage ready with food, bedding, chew toys, food dishes, a water bottle and a brush. [3]
> *[Paraphrased derived summary — non-Open-Access source.]* Put a small wooden or cardboard box inside the cage as a hiding place for security and sleeping. [3]
> *[Paraphrased derived summary — non-Open-Access source.]* Provide daily supervised out-of-cage time in a guinea-pig-proofed area free of cords and other chew hazards. [3]
> *[Paraphrased derived summary — non-Open-Access source.]* Always supervise a guinea pig outside its cage and keep the area safe and hazard-free. [3]
> *[Paraphrased derived summary — non-Open-Access source.]* Avoid sawdust (a respiratory hazard) and cat litter (indigestible) as bedding. [3]

## Behavior & Training


Guinea pigs are very social and need companion guinea pig(s) plus constant access to space, food, water, safe hiding places and toys; a change in normal behaviour can mean distress, boredom, illness or injury. [2]


Socialisation, bonding, play and preventing boredom / behaviour problems.

### Guinea Pig — behavior & socialization (communication, body language, social needs)

*All lines in this block are paraphrased derived summaries — non-Open-Access source.*

> If a guinea pig's behaviour becomes an ongoing problem, or it shows signs of stress or fear, ask a vet or clinical animal behaviourist for advice. [2]
> Keep a guinea pig happy and healthy by giving constant access to space, food, water, safe hiding places, companion guinea pig(s) and toys. [2]
> Guinea pigs are very social and need to interact with other friendly guinea pigs. [2]
> Keep a guinea pig with at least one other friendly guinea pig, unless a vet or behaviourist advises otherwise. [2]
> Guinea pigs like to tunnel, so provide materials that allow tunnelling such as pipes and deep areas of hay. [2]
> A change in normal behaviour can be a sign the guinea pig is distressed, bored, ill or injured. [2]

> Male guinea pigs establish social hierarchies in which a single alpha male dominates subordinate males. [1]
> Males are known to be extremely aggressive when competing for territory or potential mates. [1]

## Enrichment & Exercise

Toys, foraging, hiding and exercise to prevent boredom.

### Guinea Pig — enrichment (owner-practical care, Merck Veterinary Manual pet-owner)

*All lines in this block are paraphrased derived summaries — non-Open-Access source.*

> Do not use exercise wheels, which can injure guinea pigs. [3]

> *[Paraphrased derived summary — non-Open-Access source.]* Give safe, nontoxic enrichment items, store-bought or homemade. [5]

## When to call a vet NOW


- **Eating, drinking or toilet changes:** consult a vet immediately if you notice any changes in eating, drinking and/or toilet habits — for example, if droppings stop, become less frequent, or become softer than usual and stick to the back. [4]
- **Behaviour change:** a change in normal behaviour can be a sign the guinea pig is distressed, bored, ill or injured — book a vet visit if it persists. [2]
- **Changes in urination (possible stones):** urolithiasis (urinary stones) is common, and female guinea pigs (sows) are more often diagnosed with stones — consult a vet immediately for any change in toilet habits. [8] [4]
- **Sore or swollen footpads:** pododermatitis (footpad soreness) is common and can affect all four feet — book a vet visit. [9]
- **Tell your vet it is a guinea pig:** some antibiotics, including penicillins, can be fatal to guinea pigs, so always remind your vet your pet is a guinea pig before any medication. [10]


## Health & Disease


Common problems include urinary stones (more often in sows), pododermatitis of all four feet, and cystic ovaries in sows; because guinea pigs cannot make vitamin C, daily dietary vitamin C matters. [8] [9] [6]

Common conditions and their clinical signs, drawn from professional veterinary references. If you notice worrying signs, contact a species-experienced veterinarian promptly.

### Guinea pig cystic ovarian disease — most common reproductive tract disorder in sows

*All lines in this block are paraphrased derived summaries — non-Open-Access source.*

> Cystic ovaries are the most common reproductive-tract disorder in female guinea pigs (sows). [8]

### Guinea pig emergency signs — when to contact a vet

*All lines in this block are paraphrased derived summaries — non-Open-Access source.*

> Consult a vet immediately if you notice any changes in eating, drinking and/or toilet habits — for example, if droppings stop, become less frequent, or softer than usual and stick to the back. [4]
> Monitor the amount eaten/drunk and the droppings daily; guinea pigs produce hard dry pellets and softer moist pellets they re-ingest. [4]
> Avoid sudden dietary changes, as these can upset the digestive system. [4]

### Guinea pig urolithiasis — calcium-carbonate stones common, females at higher risk

*All lines in this block are paraphrased derived summaries — non-Open-Access source.*

> Urolithiasis (urinary stones) is common in guinea pigs; stones form when calcium carbonate and other crystals precipitate out of normal urine. [8]
> Female guinea pigs (sows) are more often diagnosed with stones in the ureters and urinary bladder (ureteroliths and cystoliths). [8]

### Pododermatitis in guinea pigs (common; affects all four feet; inappropriate flooring/obesity predispose)

*All lines in this block are paraphrased derived summaries — non-Open-Access source.*

> Pododermatitis (footpad soreness) is common in guinea pigs and can affect all four feet. [8]

> *[Paraphrased derived summary — non-Open-Access source.]* A 2025 study linked offering 7–10 or more types of produce to a lower chance of urinary stones. [5]

## Toxicology & Hazards

Substances and environmental hazards to avoid.

### Guinea pig antibiotic sensitivity — procaine penicillin and ampicillin GI disturbance (Merck Veterinary Manual)

*All lines in this block are paraphrased derived summaries — non-Open-Access source.*

> Guinea pigs (alongside chinchillas, birds, snakes, and turtles) are sensitive to procaine penicillin. [9]
> Broad-spectrum penicillins may lead to superinfection, and oral ampicillin can cause GI disturbances. [9]

### Guinea pig non-drug poisons — garden, household and feeding hazards

*All lines in this block are paraphrased derived summaries — non-Open-Access source.*

> Foods that can be harmful or poisonous to guinea pigs include iceberg lettuce, potato, garlic, avocado, coconut and citrus fruits — these should be avoided. [4]
> Lawnmower clippings should never be fed to guinea pigs, as they upset the digestive system and make them ill. [4]

### Penicillin toxicity syndromes in guinea pigs — toxic, hemorrhagic, chronic (Green 1974, PMID 4446629)

> The association of viral activation with penicillin toxicity in guinea pigs and hamsters. [10]
> This finding has been construed as being activation of a latent virus by this antibiotic, but the relationship, if any, of the phenomenon of viral activation to the syndromes produced by penicillin and its frequent lethal toxicity is unknown. [10]
> Of some 60 guinea pigs which received injections of penicillin three developed tumors and four others were found to have gallstones. [10]
> A virus similar or identical to the guinea pig virus also has been isolated from hamsters dying of penicillin-induced disease. [10]
> It is hypothesized that the absorption of endotoxin, resulting from the well known change in intestinal flora caused by penicillin, produces a state of immunodeficiency which regularly gives rise to activation of a latent virus, and perhaps, rarely, to the development of malignant neoplasms. [10]

> *[Paraphrased derived summary — non-Open-Access source.]* Iceberg lettuce, potato, garlic, avocado, coconut and citrus fruits are listed as harmful or poisonous for guinea pigs and must be avoided. [4]
> *[Paraphrased derived summary — non-Open-Access source.]* Foods to avoid because they can be harmful or poisonous include iceberg lettuce, potato, garlic, avocado, coconut and citrus fruits; introduce new foods gradually and avoid sudden diet changes. [4]
> *[Paraphrased derived summary — non-Open-Access source.]* Guinea pigs like to chew and may gnaw electrical cords or toxic houseplants. [3]

## Grooming

Brushing / bathing, nails, coat / skin and dental care.

### Guinea Pig — grooming (owner-practical care, Merck Veterinary Manual pet-owner)

*All lines in this block are paraphrased derived summaries — non-Open-Access source.*

> Guinea pigs need regular grooming and nail trimming. [3]
> Use nail clippers designed for small animals (or humans). [3]
> Start nail clipping when guinea pigs are young so they become accustomed to it. [3]
> Avoid cutting the quick (the blood vessel inside the nail); hold a bright light to the nail to see it in dark nails. [3]
> Use a shampoo made for small animals, since human shampoo can dry the skin. [3]
> Long-haired breeds need regular brushing to prevent matting. [3]
> Health checks should look for bright clean eyes, a clear nose/ears/anus, formed stool, clean teeth with the upper front teeth overlapping the lower ones, even weight on all four feet, and no foot sores or flaky skin; housing should also be clean, low-odour and not overcrowded. [3]

> They are active during dusk and dawn (crepuscular) and when not sleeping, spend a majority of their time grooming, feeding, or investigating the local environment. [1]
> *[Paraphrased derived summary — non-Open-Access source.]* Trim nails regularly to prevent overgrowth and injury to handlers. [3]

## Breeding & Neutering

Neutering / spaying, reproduction and preventing unwanted litters.

### Guinea Pig — breeding (owner-practical care, Merck Veterinary Manual pet-owner)

*All lines in this block are paraphrased derived summaries — non-Open-Access source.*

> To avoid breeding, keep same-sex groups or have a vet spay/neuter the animals before housing opposite-sex pairs together. [3]
> Male guinea pigs living together fight less if neutered or introduced before weaning. [3]
> When buying from a breeder, shelter or store, ask about a veterinary exam beforehand, or whether the seller will take back an animal found sick or pregnant by a vet. [3]

> Guinea pigs no longer exist in the wild, therefore, mating systems in natural environments are unknown. [1]
> In domestic populations, mating is heavily influenced by humans. [1]
> Prior to mating, males smell a potential mate's genital area and scent mark their mates with urine. [1]

## Regulations & Legality

Legality crosswalk lines for this species, where available. Jurisdiction-specific pet law is frequently a gap — see the roadmap.

### Guinea Pig — species legality crosswalk (US/CA/FL named lists + EU/JP/CITES framework)

> Guinea Pig — EU-IAS: Not on the landed EU Union list of IAS of Union concern (species not enumerated) — Art 7 prohibition applies only to listed species. Basis: Negative finding: enumerated scan of landed EU Union list.
> Guinea Pig — JP-IAS: Not designated in the landed JP specified-invasive alien species list (species not enumerated) — Art 4 prohibition applies only to designated species. Basis: Negative finding: enumerated scan of landed JP designated list.

## Appendix A — Commercial Food & Regulatory Notes

How pet-food regulatory standards treat this species (reference material, demoted from the main flow).

### Exotic / specialty pet food — AAFCO recognizes no nutrient profiles for exotics; standards defer to NRC species reports

> As an AAFCO-recognized nutrient profile or nutritional authority: [11]
> For dogs, the AAFCO Dog Food Nutrient Profiles; [11]
> For cats, the AAFCO Cat Food Nutrient Profiles; [11]
> For specialty pets, the nutrient recommendations approved by the Committee on Animal Nutrition of the National Research Council of the National Academy of Sciences [11]

## Appendix B — Research Evidence

Peer-reviewed papers indexed for this species (reference material). Entries whose abstract did not mention the species by name, or were flagged off-topic at source, were omitted as likely mis-clustered.

### Evidence cluster — Guinea pig (Cavia porcellus) clinical cases (peer-reviewed, Europe PMC)

> **PMID 42076742 (2026, Veterinary sciences)** — Multidrug-Resistant Escherichia coli Causing Respiratory and Systemic Infection in a Guinea Pig (Cavia porcellus) in Romania: A Case Report. (opening): Background/objectives Multidrug-resistant (MDR) Escherichia coli has increasingly been recognized as a pathogen capable of causing severe systemic infections in various animal species. However, reports describing respiratory and septicemic infections caused by MDR E. coli in guinea pigs remain scarce. The objective of this report was to describe the clinical, pathological, and microbiological findings associated with a fatal infection in a domestic guinea pig. Case study A 10-month-old female guinea pig ( Cavia porcellus ), kept as a companion animal in a household environment, presented with acute respiratory distress, lethargy, and anorexia, progressing rapidly to death within approximately 36 h of onset. Post-mortem examination revealed severe pulmonary congestion, diffuse inflammatory lesions in the trachea, and generalized vascular congestion in multiple organs. Bacteriological cultures obtained from lung and bone marrow samples yielded pure growth of Escherichia coli. Identification was confirmed using MALDI-TOF mass spectrometry. Antimicrobial susceptibility testing demonstrated resistance to several antibiotic classes, including β-lactams, fluoroquinolones, tetracyclines, sulfonamides, and phenicols, while susceptibility was retained only to aminoglycosides. Molecular analysis revealed the presence of virulence genes involved in adhesion and iron acquisition, supporting the pathogenic potential of the isolate. Conclusions This report highlights the ability of MDR E. coli to cause severe respiratory and systemic infections in guinea pigs. The findings underline the importance of early diagnosis, appropriate antimicrobial stewardship, and improved husbandry conditions in preventing such infections. From a One Health perspective, the circulation of resistant strains in companion animals may represent a potential risk for both environmental and human health. [12]
> **PMID 42245977 (2026, Frontiers in veterinary science)** — Uterine choriocarcinoma associated with ovarian cysts in a Cavia porcellus: a clinical case. (opening): A 3. 5-year-old female guinea pig was presented for suspected hematuria. Hematology, serum biochemistry, urinalysis, and fecal examination were within normal limits; however, diagnostic imaging revealed multiple ovarian cysts and a uterine mass without evidence of metastasis. The animal underwent an ovariohysterectomy to remove the mass but died 6 h after anesthetic recovery. Histopathological examination identified a uterine adenoma with focal choriocarcinoma, associated with polycystic ovarian disease. To the authors' knowledge, this represents only the second reported case of uterine choriocarcinoma in the guinea pig. To the authors' knowledge, this is the first reported case of uterine choriocarcinoma in a guinea pig documented with a complete clinical, surgical, diagnostic imaging, histopathological, and necropsy evaluation. [13]

### Evidence cluster — Guinea pig (Cavia porcellus) husbandry, health & nutrition (peer-reviewed, Europe PMC)

> **PMID 42071946 (2026, Animals: an open access journal from MDPI)** — Occurrence and Genetic Diversity of Cryptosporidium spp. in Pet Rodents from Yunnan, China: Identification of Zoonotic Subtypes in Hamsters. (opening): Cryptosporidium spp. are common protist pathogens, and the growing popularity of pet rodents raises concerns about their potential role in zoonotic parasites transmission. However, epidemiological data on Cryptosporidium spp. in pet rodents in Yunnan Province is scarce. To examine the occurrence of Cryptosporidium spp. in pet rodents in Yunnan, we collected 762 fecal samples from four rodent species across four cities. Nested PCR and DNA sequencing were used to characterize the species and subtypes of Cryptosporidium. The occurrence of Cryptosporidium spp. in guinea pigs ( Cavia porcellus ), Siberian dwarf hamsters ( Phodopus sungorus ), Syrian hamsters ( Mesocricetus auratus ) and fancy rats ( Rattus norvegicus domestica ) was 18.7% (80/426), 17.3% (36/207), 12.5% (15/120), 0% (0/9), respectively, with an overall rate of 17.2% (131/762). According to regions, the positivity rate of Cryptosporidium spp. in Zhaotong city, Kunming city, Yuxi city and Qujing city was 21.0%, 17.9%, 16.8% and 10.5%, respectively. In terms of sampling location, the occurrence of Cryptosporidium spp. in pet markets, farms and shops was 19.5%, 18.6% and 0%, respectively. Sequence analysis of the small subunit ribosomal RNA ( SSU rRNA) gene identified six Cryptosporidium species/genotypes: Cryptosporidium homai ( n = 52), Cryptosporidium wrairi ( n = 30), Cryptosporidium sp. hamster genotype ( n = 25), Cryptosporidium andersoni ( n = 20), Cryptosporidium parvum ( n = 5), and Cryptosporidium muris ( n = 1). Further subtyping of C. andersoni isolates using multilocus sequence typing (MLST) revealed a single subtype, with all isolates identified as A3A4A2A2. All five C. parvum isolates were identified as subtype IIdA15G1 based on the gp60 gene. Our findings demonstrated the presence of the zoonotic C. parvum IIdA15G1 subtype in pet rodents, suggesting that these animals, particularly hamsters, may serve as reservoirs for human-pathogenic Cryptosporidium species. These results underscore the need for improved biosecurity and husbandry practices in the pet rodent trade to mitigate public health risks. *[CC BY — Open Access, verbatim with attribution.]* [14]
> **PMID 41630840 (2026, One health (Amsterdam, Netherlands))** — Molecular detection of zoonotic RNA viruses in guinea pigs (Cavia porcellus) from small-scale family farming in the region of Cusco, Peru. (opening): Emerging zoonotic diseases are frequently associated with close human-animal interactions in small-scale farming systems. Guinea pigs ( Cavia porcellus ) are widely raised for food in the Andean region, often under poor sanitary conditions; however, little is known about their role as reservoirs of enteric viruses with zoonotic potential. This study aimed to detect zoonotic RNA viruses in intestinal samples from guinea pigs raised on small-scale family farms in the Cusco region of Peru. A total of 34 intestinal tissue samples from adult guinea pigs showing gastrointestinal lesions were analyzed by reverse transcription polymerase chain reaction (RT-PCR) and nested PCR for the molecular detection of Coronavirus (CoV), Rotavirus A (RVA), Mammalian orthoreovirus (MRV), and Kobuvirus (KoV). Positive amplicons were sequenced and analyzed phylogenetically to confirm the PCR assays. Overall, 91.18% (31/34) of samples tested positive for at least one virus. RVA was the most frequently detected (58.82%), followed by CoV (29.41%), MRV (23.53%), and KoV (23.53%). Single-virus infections accounted for 20 cases and co-infections were identified in 11 cases. RVA was the most frequently detected, both in single ( n = 9) and co-infections ( n = 11). KoV detection was predominantly associated with co-infections rather than single infections. These findings provide the first molecular evidence of multiple zoonotic RNA viruses in guinea pigs from small-scale farming in Peru, highlighting their potential role as reservoirs in zoonotic transmission cycles. Enhanced surveillance and improved farm-level biosecurity are essential to mitigate risks of viral emergence in these traditional farming systems. *[CC BY — Open Access, verbatim with attribution.]* [15]
> **PMID 42023055 (2026, Applied sciences (Basel, Switzerland))** — Hexavalent Chromium Oropharyngeal Aspiration Induced Behavior Effects and Essential Metal Dyshomeostasis in Young Hartley Guinea Pigs. (opening): Hexavalent chromium [Cr(VI)] is the toxic form of chromium often used in industry for its hardness, bright colors, and anticorrosive properties. Cr(VI) is a known human lung carcinogen, making its inhalation an occupational hazard. Growing evidence emphasizes the neurotoxic potential of Cr(VI), though it is not linked to brain cancers. Few studies consider neurotoxicity in chromate workers, reporting impaired olfactory discrimination and an increased risk of death from mental health disorders. A major factor limiting translation of most rodent Cr(VI) studies to human populations has to do with vitamin C, which can reduce the toxic Cr(VI) to non-toxic Cr(III). Rats and mice synthesize vitamin C and are likely more resistant to Cr(VI) than humans. Here, we considered Cr(VI) neurotoxicity in guinea pigs ( Cavia porcellus ), which do not endogenously synthesize vitamin C. We exposed Hartley guinea pigs (both sexes) to occupationally relevant concentrations of Cr(VI) via oropharyngeal aspiration weekly for 90 days. We observed behavioral effects in the open field assay, elevated plus maze, Y-maze, and novel object recognition test during weeks 9-12 of exposure. After euthanasia, we assessed Cr accumulation and essential metal dyshomeostasis in the hippocampus. We observed significantly increased hippocampal Cr accumulation in females, while males exhibited essential metal dyshomeostasis. *[CC BY — Open Access, verbatim with attribution.]* [16]

## References

[1] https://animaldiversity.org/accounts/Cavia_porcellus/  
    *grade B: T3 professional reference, verbatim (computed per docs/topic_grading_guide.md §4)*
[2] https://www.rspca.org.uk/adviceandwelfare/pets/rodents/guineapigs/behaviour  
    *grade C: T4 expert organisation, paraphrase (computed per docs/topic_grading_guide.md §4)*
[3] https://www.merckvetmanual.com/all-other-pets  
    *grade B: T3 professional reference, paraphrase (computed per docs/topic_grading_guide.md §4)*
[4] https://www.rspca.org.uk/adviceandwelfare/pets/rodents/guineapigs/diet  
    *grade C: T4 expert organisation, paraphrase (computed per docs/topic_grading_guide.md §4)*
[5] https://www.merckvetmanual.com/exotic-and-laboratory-animals  
    *grade B: T3 professional reference, paraphrase (computed per docs/topic_grading_guide.md §4)*
[6] https://www.merckvetmanual.com/exotic-and-laboratory-animals/rodents/guinea-pigs  
    *grade B: T3 professional reference, paraphrase (computed per docs/topic_grading_guide.md §4)*
[7] https://www.merckvetmanual.com/exotic-and-laboratory-animals/guinea-pigs/housing-and-nutrition-of-guinea-pigs  
    *grade B: T3 professional reference, paraphrase (computed per docs/topic_grading_guide.md §4)*
[8] https://www.merckvetmanual.com/exotic-and-laboratory-animals/guinea-pigs/noninfectious-diseases-of-guinea-pigs  
    *grade B: T3 professional reference, paraphrase (computed per docs/topic_grading_guide.md §4)*
[9] https://www.merckvetmanual.com/  
    *grade B: T2 peer-reviewed/T3 professional reference, paraphrase (computed per docs/topic_grading_guide.md §4)*
[10] https://pmc.ncbi.nlm.nih.gov/articles/PMC2595098/  
    *grade A: T2 peer-reviewed, verbatim (computed per docs/topic_grading_guide.md §4)*
[11] AAFCO — Dog / Cat / Specialty-Pet Food Nutrient Profiles (NRC for specialty pets) — https://www.aafco.org/  
    *grade A: T1 government/standard, verbatim (computed per docs/topic_grading_guide.md §4)*
[12] https://pubmed.ncbi.nlm.nih.gov/42076742/  
    *grade A: T2 peer-reviewed, verbatim (computed per docs/topic_grading_guide.md §4)*
[13] https://pubmed.ncbi.nlm.nih.gov/42245977/  
    *grade A: T2 peer-reviewed, verbatim (computed per docs/topic_grading_guide.md §4)*
[14] https://pubmed.ncbi.nlm.nih.gov/42071946/  
    *grade A: T2 peer-reviewed, verbatim (computed per docs/topic_grading_guide.md §4)*
[15] https://pubmed.ncbi.nlm.nih.gov/41630840/  
    *grade A: T2 peer-reviewed, verbatim (computed per docs/topic_grading_guide.md §4)*
[16] https://pubmed.ncbi.nlm.nih.gov/42023055/  
    *grade A: T2 peer-reviewed, verbatim (computed per docs/topic_grading_guide.md §4)*

## Supplement Data Roadmap

*Known gaps in this manual, machine-checked against the published text on every build; an item appears only while the gap is still real.*

- **Root-domain reference(s)**: https://www.merckvetmanual.com/, https://www.aafco.org/ — these point to a source home page rather than the exact page; being fixed.