Domesticated guinea pigs are intelligent mammals known scientifically as Cavia porcellus. They are a South American rodent belonging to the Cavy family and descended from wild guinea pigs.
Misconceptions About Guinea Pig Relatives
Some people mistakenly believe that guinea pigs are closely related to rats and mice because they are all rodents. However, research shows that guinea pigs evolved separately, forming their own unique group that isn’t as similar to other rodents as previously thought.
There is also a misconception that guinea pigs are close relatives of pigs and rabbits. While they are all mammals, they are not closely related. In fact, guinea pigs have a much stronger connection to the capybara. Capybaras not only resemble giant guinea pigs, but they are also members of the cavy family.
Guinea Pig Ancestry
Evidence suggests that the domesticated guinea pigs we know today descended from some of their closest wild relatives, including:
- Cavia tschudii (Montane guinea pig)
- Cavia aperea (Brazilian guinea pig)
- Cavia fulgida (Shiny guinea pig)
Out of these, the Montane guinea pig, which is native to the Andes, is believed to be the closest wild relative to our domesticated guinea pig.
Prehistoric Guinea Pigs
In the 1990s, scientists discovered and excavated a nearly complete skeleton of Phoberomys pattersoni, often described as a “giant guinea pig,” in northwestern Venezuela, South America.
Phoberomys roamed the region between six to eleven million years ago, weighing around 700 kilograms (over 1,500 pounds). This is about the size of a rhinoceros and over ten times larger than the modern-day capybara, the largest living rodent.
This giant guinea pig, which is now extinct, was an evolutionary cousin of the cavy family, including our pet guinea pigs.
Phoberomys probably inhabited swamps, rivers, lagoons, and coastal marshes, grazing on abrasive vegetation such as seagrasses. Its predators included some of the largest crocodiles, alligators, and caimans to have ever existed.
Guinea Pig Family Tree
The Caviidae family is a group of rodents known as cavies that are native to South America. Within this family, there is a subgroup called Caviinae, which includes domestic guinea pigs and other related species.
This family tree shows the Caviidae family and illustrates how different species within it are related to one another. There are species in the Caviidae family that have become extinct and are not included in this example.
- CAVIINAE
- Guinea Pigs or Cavies (Genus Cavia)
- Yellow-toothed cavy (Genus Galea)
- Southern highland yellow-toothed cavy (Galea comes)
- Brazilian yellow-toothed cavy (Galea flavidens)
- Lowland yellow-toothed cavy (Galea leucoblephara)
- Common yellow-toothed cavy (Galea musteloides)
- Muenster yellow-toothed cavy (Galea monasteriensis)
- Spix’s yellow-toothed cavy (Galea spixii)
- Mountain Cavy (Genus Microcavia)
- Southern Mountain Cavy (Microcavia australis)
- Jayat’s Mountain Cavy (Microcavia jayat)
- Thomas’s Mountain Cavy (Microcavia maenas)
- Andean Mountain Cavy (Microcavia niata)
- Shipton’s Mountain Cavy (Microcavia shiptoni)
- Sorojchi Mountain Cavy (Microcavia sorojchi)
- DOLICHOTINAE
- Mara (Genus Dolichotis)
- Patagonian Mara (Dolichotis patagonum) – also known as Patagonian Hare
- Genus Pediolagus
- Chacoan Mara (Pediolagus salinicola)
- Mara (Genus Dolichotis)
- HYDROCHOERINAE
- Capybaras (Genus Hydrochoerus)
- Greater Capybara (Hydrochoerus hydrochaeris)
- Lesser Capybara (Hydrochoerus isthmius)
- Rock Cavy (Genus Kerodon)
- Climbing Cavy (Kerodon acrobata)
- Rock Cavy (Kerodon rupestris)
- Capybaras (Genus Hydrochoerus)
Closest Wild Relatives to the Guinea Pig
Brazilian guinea pig (Cavia aperea)
The Brazilian Guinea Pig, with a body length of approximately 272 mm is narrower and longer than domesticated guinea pigs. Their coat is dark brown-black, while the underside is pale grey with a hint of yellow.
They inhabit several South American countries, including Colombia, Ecuador, Venezuela, and northern Argentina. This species lives at altitudes from 400 to 3,000 metres above sea level, mainly in open grassland and on the savannah, feeding on grasses and herbs. The Brazilian Guinea Pig creates a labyrinth of surface tunnels through the vegetation.
Shiny guinea pig (Cavia fulgida)
The Shiny Guinea Pig, measuring between 220 and 270 mm in length, has a brown shiny coat and is native to Brazil. Specific details about its habitat preferences are not well-documented, but research suggests they live in forests and grasslands, as well as flooded marshlands in central Brazil. There are indications that this species may prefer semi-mountainous areas along the coast.
Montane guinea pig (Cavia tschudii)
The Montane Guinea Pig comes from the Andes mountains in South America. It is found in a range that extends from Peru in the north to the Tarapacá Region in Chile and the Tucumán Province in northern Argentina.
Their colouration can vary depending on which part of South America they live from a dark red-brown with black to a much paler brown.
These guinea pigs live in rocky yet moist environments with rough vegetation, creating pathways through the foliage to move through their surroundings. In Argentina, montane guinea pigs inhabit complex burrow systems that have many entrances.
Greater guinea pig (Cavia magna)
The Greater Guinea Pig, which measures 310 mm in length, is a semi-aquatic species (lives both on land and in water) native to the coastal regions of Brazil and Uruguay. The colouration is a dark agouti brown on the back with a red-brown underside.
It thrives in moist grasslands, marshes, woodland edges, and small valleys. Unlike other guinea pigs, it has membranes joining the toes and is well-adapted for navigating the wet environments it lives in. This species makes complex networks of tunnels and runways through the vegetation.
Santa Catarina’s guinea pig (Cavia intermedia)
The Santa Catarina’s Guinea Pig, native to the Moleques do Sul Archipelago in Santa Catarina, South Brazil, is critically endangered. Its estimated population is just 24 to 60. This guinea pig has the smallest geographical distribution of any known mammal, occupying only 10 acres (40,000 square metres).
They are brown or grey and measure 200 to 400mm in length. Interestingly, unlike most other species, there is no size difference between males and females.
These rare guinea pigs inhabit grasslands where they feed on grasses and find shelter in bushes or other dense vegetation.
Information from some scientific studies and archaeological reports was used in this article. Here are some of the sources:
https://pubmed.ncbi.nlm.nih.gov/2052090/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4137285/
https://www.researchgate.net/publication/9087813_The_Anatomy_of_the_World’s_Largest_Extinct_Rodent