Indigenous peoples of South America knew capybaras intimately for thousands of years before any European set eyes on them, but the animal entered Western scientific literature through a specific chain of events stretching from the 1630s to 1766. The first detailed European descriptions came from Georg Markgraf, a German naturalist working in colonial Brazil during the Dutch occupation, and the formal Latin name was assigned over a century later by Carl Linnaeus. The story of how the world’s largest living rodent got its names, both common and scientific, winds through Tupi-Guaranà linguistics, colonial natural history, Enlightenment taxonomy, and modern molecular genetics.
Thousands of Years Before Europeans Arrived
Capybaras were not “discovered” in any meaningful sense by Europeans. The peoples of South America had been hunting, eating, and living alongside these animals since long before recorded history. Archaeological evidence from the Atlantic Forest coast of Brazil shows that selective hunting of medium- and large-bodied native mammals, capybaras among them, has been going on for over 4,500 years.1Tropical Conservation Science. Long-Term Perspective on Fishing and Mammal Defaunation in the Atlantic Forest Coast of Brazil Using Archaeological Faunal Remains These animals were a familiar, everyday presence across a vast range of the continent, from Panama south through Argentina, wherever there was water and grassland.
The common name “capybara” itself is a legacy of that indigenous familiarity. It derives from Tupi-GuaranÃ, one of the major language families of lowland South America. The word is generally traced to something like kapiÿva or kaapi’wara, which translates roughly as “grass eater” or “one who eats slender leaves.” That name encapsulates the animal’s most conspicuous habit: grazing on grasses and aquatic vegetation along riverbanks. When Portuguese and Spanish colonists adopted the word, they adapted the pronunciation, and through centuries of use, it became “capybara” in English and “capivara” in Portuguese.
Georg Markgraf and the First European Descriptions
The first European to produce detailed natural history illustrations and descriptions of the capybara was Georg Markgraf (1610–1644), a German astronomer and naturalist who traveled to northeastern Brazil as part of a scientific expedition organized under the Dutch West India Company. The Dutch had seized parts of northeastern Brazil from Portugal in the 1630s, and the colony’s governor, Johan Maurits van Nassau-Siegen, was unusually interested in science and the natural world. He brought along Markgraf and the physician Willem Piso to document the region’s flora, fauna, and geography.
Markgraf produced extensive notes and illustrations of Brazilian animals, including the capybara, before his early death in 1644 at just 34 years old, likely from malaria. His work was published posthumously in 1648 as part of Historia Naturalis Brasiliae, one of the most important early works of natural history from the Americas. This book gave European readers their first serious look at a huge range of South American species, and Markgraf’s capybara illustrations would prove pivotal. More than a century later, when Linnaeus needed to formally classify the animal, it was Markgraf’s illustrations he relied on, since no preserved specimen was available to serve as a reference.
The 1766 Linnaean Classification
Carl Linnaeus, the Swedish naturalist who devised the system of binomial nomenclature still used today, formally described the capybara in 1766 in the twelfth edition of his Systema Naturae. He assigned it the name Sus hydrochaeris, initially placing it with pigs in the genus Sus. This was not as strange as it sounds. European colonists and naturalists routinely compared capybaras to pigs because of their stocky, barrel-shaped bodies, their grunting vocalizations, and their semi-aquatic habits. The species epithet hydrochaeris comes from Greek roots meaning “water” (hydro) and “joy” or “grace” (charis), so the name loosely translated to “water pig” or “water hog.”
What made Linnaeus’s description unusual was that he worked not from a preserved specimen but from Markgraf’s published illustrations. This meant there was no physical holotype, the actual preserved animal that serves as the permanent reference point for a species name. That gap in the record persisted for nearly 250 years. It was not until 2013 that researchers formally designated a neotype, a replacement reference specimen, for the capybara, depositing it in the mammal collection at the Universidade Federal da ParaÃba in Brazil.2Biological Journal of the Linnean Society. Growing prominence of natural history collections in the Global South: impacts on the taxonomy of Neotropical non-volant small mammals The fact that it took until 2013 to sort out such a basic piece of nomenclatural housekeeping for one of the most recognizable mammals in South America speaks to how chaotic early taxonomy could be.
Why “Water Pig” Stuck Around in the Scientific Name
The capybara was soon moved out of the pig genus, but the watery theme persisted. Later taxonomists placed it in its own genus, Hydrochoerus, from the Greek hydro (water) and choiros (pig). Combined with the original species name, the full binomial Hydrochoerus hydrochaeris is essentially saying “water pig” twice, in slightly different Greek constructions. This kind of redundancy is not uncommon in taxonomy; it happens when a genus gets renamed but the original species epithet, assigned by Linnaeus, is retained by the rules of zoological nomenclature.
Other regional names for the animal reflect the same themes European observers latched onto. In parts of South America, the capybara goes by “carpincho” (from GuaranÃ), “chigüire” in Venezuela, and “ronsoco” in Peru. The Venezuelan name “chigüire” has become so culturally embedded that the animal is a national icon of sorts, featured in jokes, memes, and the famous tradition of eating capybara meat during Lent, since the Catholic Church at one point classified it as a fish for fasting purposes due to its semi-aquatic lifestyle.
The Long Debate Over Where Capybaras Belong
For most of the twentieth century, capybaras were placed in their own family, Hydrochaeridae, reflecting the view that they were distinct enough from other South American rodents to warrant a separate grouping. They are, after all, dramatically larger than their closest relatives and have some distinctive features, like partially webbed feet and eyes, ears, and nostrils positioned high on the head for swimming.
Molecular evidence has redrawn that picture. Genetic studies using nuclear and mitochondrial DNA showed that capybaras are actually nested within the family Caviidae, the group that includes guinea pigs, rock cavies, and maras. Keeping capybaras in their own separate family made the Caviidae paraphyletic, meaning the family tree excluded some descendants of a common ancestor while including others. One molecular phylogeny found that the rock cavy (Kerodon), traditionally grouped with guinea pigs, is actually more closely related to capybaras than to guinea pigs, further scrambling the old classification.3Oxford Academic. Phylogenetic Relationships, Ecological Correlates, and Molecular Evolution Within the Cavioidea (Mammalia, Rodentia) Most modern classifications now place capybaras within Caviidae, making them essentially oversized guinea pig relatives rather than a standalone family.
This reclassification is a good example of how scientific naming is not a one-time event. A species gets described and classified, but the classification gets revised as new evidence comes in. The capybara has been Sus hydrochaeris, the sole member of Hydrochaeridae, and now a member of Caviidae, all without the animal itself changing one bit.
An Evolutionary Lineage Millions of Years Deep
The capybara’s family tree extends far deeper than the few hundred years of Western scientific observation. The broader group of caviid rodents underwent major diversification events millions of years ago in South America, when the continent was still isolated from North America. Fossil evidence documents at least two major radiations of caviid-like rodents, one during the Deseadan period (roughly 29 to 24 million years ago) and another during the Santacrucian (roughly 18 to 15 million years ago).4PLoS ONE. Major Radiations in the Evolution of Caviid Rodents: Reconciling Fossils, Ghost Lineages, and Relaxed Molecular Clocks Most lineages from those early radiations went extinct during the Miocene; the only one that survived to produce today’s living species is the lineage leading to Caviidae.
Among the extinct relatives were some truly enormous animals. Josephoartigasia monesi, which lived around 2 to 4 million years ago in what is now Uruguay, is estimated to have weighed roughly a ton, making it the largest rodent that ever lived. Today’s capybara, at around 50 to 65 kilograms for an adult, is a modest creature by comparison. But it is still the largest living rodent by a wide margin, and understanding how it got so big relative to guinea pigs and other caviids has become a question genomic science can now tackle.
What the Capybara Genome Reveals About Gigantism
Researchers assembled a draft genome of the capybara to investigate the genetic basis of rodent gigantism. Among the findings were gene-family expansions specific to the capybara lineage, including a putative new anticancer mechanism involving T-cell-mediated tumor suppression.5Molecular Biology and Evolution. How to Make a Rodent Giant: Genomic Basis and Tradeoffs of Gigantism in the Capybara, the World’s Largest Rodent This is an intriguing result because larger body size generally correlates with more cell divisions over a lifetime, which should mean a higher risk of cancer-causing mutations. The fact that capybaras appear to have evolved a specific molecular countermeasure to that risk suggests that getting big came with biological tradeoffs that had to be resolved at the genetic level.
The genome work also confirmed what the molecular phylogeny studies had shown: capybaras are firmly embedded within the caviid radiation, closely related to guinea pigs and rock cavies. Their dramatic size difference from those relatives is a relatively recent evolutionary development, driven by selection pressures we can now begin to trace gene by gene.
The Lenten Fish Classification
One of the stranger chapters in capybara naming history has nothing to do with science and everything to do with Catholic dietary law. During the colonial period in South America, Catholic missionaries and settlers petitioned the Vatican to classify the capybara as a type of fish for the purposes of Lent, when eating meat from warm-blooded animals was forbidden. The argument rested on the animal’s semi-aquatic lifestyle: it spends much of its time in water, has webbed feet, and can hold its breath for several minutes. The Church apparently granted the request, and capybara meat became a Lenten staple in parts of Venezuela, Colombia, and Brazil.
This classification was never a scientific one, of course. It was a practical accommodation for colonists and indigenous converts in a region where capybara was a major protein source. But the tradition persists. In Venezuela, capybara meat is still widely consumed during Holy Week, and “chigüire” remains culturally significant in ways that go well beyond taxonomy. The episode is a reminder that how an animal gets categorized depends heavily on who is doing the categorizing and why. Indigenous peoples named it for what it ate. European naturalists named it for what it looked like. The Church named it for where it swam.
Two Species, Not One
Most people think of “the capybara” as a single species, but there are actually two recognized species in the genus Hydrochoerus. The greater capybara, Hydrochoerus hydrochaeris, is the familiar large species found across most of South America east of the Andes. The lesser capybara, Hydrochoerus isthmius, is a smaller species found in Panama, Colombia, Venezuela, and parts of northwestern South America. The lesser capybara weighs roughly 28 to 30 kilograms, about half the weight of its larger cousin, and occupies a somewhat different range, preferring more northwestern habitats.
H. isthmius was described in 1912 by the American mammalogist Edward Alphonse Goldman, well over a century after Linnaeus named the greater capybara. Its status has occasionally been debated, with some researchers treating it as a subspecies rather than a full species, but most current taxonomic treatments recognize it as distinct. The two species do not appear to overlap much in range, and they differ in skull morphology and body size in addition to their geographic separation. For most of the public conversation about capybaras, including the recent explosion of capybara popularity on social media, it is the greater capybara that people are seeing and talking about.
How Capybaras Became Internet Famous
The capybara’s rise to global celebrity status over the past decade is a phenomenon that would have baffled Markgraf, Linnaeus, and certainly the Tupi-Guaranà speakers who named the animal centuries ago. Viral photos and videos of capybaras sitting calmly in hot springs, socializing with other animals, or simply looking unbothered in unusual settings turned the species into a symbol of relaxation and friendliness online. The “OK I pull up” meme, set to a song by the rapper Gunna, cemented capybaras as one of the defining animal memes of the early 2020s.
This internet fame has had real-world consequences. Demand for capybaras as exotic pets has increased in parts of Asia, particularly Japan, where capybara cafés and petting zoos have operated for years. In parts of South America, wild capybara populations have expanded into urban areas, particularly in Argentina and Brazil, creating conflicts with suburban residents and raising questions about wildlife management. The animal that indigenous South Americans hunted for millennia, that Markgraf sketched in colonial Brazil, and that Linnaeus classified from those sketches is now a global pop-culture figure, known and adored by millions of people who will never see one in the wild.