TAXONOMY & NOMENCLATURE * *How Do We Know This? Like living animals, fossil remains of once-living animals
classified and grouped according to their relationships
each other and to their ancestors.
Casteñada & Miller 2004) (Deschamps et al 2007) (Deméré 2006) (Flynn et al 2005) (Kaspar & McClure 1976) (Kurtén 1980) (McKenna & Bell 1997) (Mones & Ojasti 1986) (Prado et al 1998) (Rowe & Honeycutt 2002) (Wyss et al 1993)
Gene studies suggest the capybara should be in their own family, Hydrochoeridae, separate from the cavy's family, Caviidae. (Rowe & Honeycutt 2002)
Several generic names have been suggested for living capybara: Hydrochaeris and Hydrochoerus are used most often. (Mones & Ojasti 1986)
Many taxonomists name three capybara subfamilies. (McKenna & Bell 1997)
Prado et al (1998) note there are currently four subfamilies, but two of them are not valid according to cladistic analysis.
One valid subfamily, the Hydrochoerinae, includes modern capybara and extinct genera; the other, Protohydrochoerinae, includes a giant capybara the size of a donkey.
Hay (1923) named Hydrochoerus pinckneyi fossils from South Carolina.
In 1926 Hay placed Hydrochoerus pinckneyi in the new genus, Neochoerus.
Mones and Ojasti (1986) note that many references to Hydrochoerus (=Hydrochaeris) in paleontology literature for North America should actually be Neochoerus and that only one South American fossil species of Hydrochoerus can be distinguished from the living capybara.
Capybara and other animals similar to cavies may have originally arrived in South America from Africa. (Wyss et al 1993)
Ancestors of modern capybara are the cavy-like rodents (cavimorphs)
Discovered in 37.5 to 31.5 million years-old rocks (Late Eocene to Early Oligocene)
in Chilean Andes
(Wyss et al 1993)
Capybara family (Hydrochoeridae)
needs revision (Deschamps et al 2007)
Geologically oldest capybaras are found in 9 million year-old rocks (Late Miocene) in Argentina (Deschamps et al 2007)
The capybara family was quite diverse during the Miocene and Pliocene; by Pleistocene times it had declined significantly. (Prado et al 1998)
Neochoerus is the most common extinct capybara in North America
between 3.6 million years ago (Pliocene) and the end of the Pleistocene
(Mones & Ojasti 1986)
A new 2.6 to 3.7 million year-old (Late Pliocene) species of Hydrochaeris discovered on island of Grenada in the Caribbean Sea
Researchers speculate the capybara might have arrived by swimming at a time of lowered sea level
Late Pleistocene record of Hydrochoeridae in southern California near Oceanside. (Deméré 2005)
DISTRIBUTION & HABITAT * *How Do We Know This? Scientists use knowledge of the earth's rocks, global plate tectonic movements,
and the chemical process of fossilization
to make sense of fossil distribution patterns and ancient habitats.
(Casteñada & Miller 2004) (Deméré 2006) (Flynn et al 2005) (Kurtén 1980)
From Florida to southern Texas, Arizona, South Carolina, West Indies, Central America, Mexico
(Kurtén 1980) (Flynn et al 2005)
Island of Grenada in the Lesser Antilles
Hydrochoerus sp. (=Hydrochaeris) in Columbia and Bolivia
A Late Pleistocene capybara was discovered 1995 in southern California near Oceanside. (Deméré 2006)
This 200,000 year-old fossil is the only one known from California
Fossil capybara are so similar to modern capybara anatomy that researchers assume they too needed habitats near plentiful fresh water.
Fossil capybara are typically found in geologic setting that indicate rivers, streams, lakes, marshes.
PHYSICAL CHARACTERISTICS* *How Do We Know This? Careful study of fossil bone or tooth anatomy yields much exact information
about placement and strength of muscles, tendons, ligaments, nerves, and blood vessels.
In rare cases, skin and hair impressions or actual skin or hair is preserved.
Body weight is more difficult to gauge because fat leaves no impression on the skeleton.
(Kurtén 1988) (Kurtén and Anderson 1980) (Macdonald & Herrera 2001) (Mones & Ojasti 1986)
Estimated Body Weight: Neochoerus pinckneyi: about 33% larger than modern capybara which weighs 48.9 kg (108 lb)
Estimated Head/Body Length: Neochoerus pinckneyi: around 180 cm (6 ft)
Tail Length: Capybaras have vestigal tails.
Neochoerus pinkneyi was a large barrel-shaped rodent with a large head and short legs; modern capybara are 33% smaller.
Cheek teeth grew throughout life in all dimensions; cutting and grinding surfaces became more complex as animal aged. (Mones & Ojasti 1986)
Incisor teeth are slightly grooved. (Kurtén 1988)
Lower incisors more compressed than those of living capybara. (Kurtén 1988)
Presumed like modern capybara: long, coarse, sparse.
In modern capybara males and females are about the same size, although males are more robust.
Other Physical Characteristics
Neochoerus like all members of its subfamily has a 4th molar as long as the other three. (Macdonald & Herrera 2001)
BEHAVIOR & ECOLOGY*
*How Do We Know This? Since direct observation of a fossil animal's behavior isn't possible, paleontologists
comparison and contrast with living animals for guidance. Tracks can sometimes
reveal further clues.
(Herrera & Macdonald 1989, 1993)
Extinct Pleistocene capybara assumed to be gregarious, highly social, like their living relatives.
Similar skull, limbs and skeletal proportions to modern capybara suggest similar non-specialized, but competent, swimming ability.
Many predators - mammals, birds, and reptiles would have fed on capybara.
DIET & FEEDING* *How Do We Know This? Clues to fossil mammals' diets come from teeth,skull shape,
from fossil dung and gut contents, from
lab analysis of oxygen
in bone and teeth,
looking at diets of similar modern animals.
(Koenigswald et al 1999) (MacFadden 1997)
High crowned (hypsodont) capybara teeth suggest a plant diet largely focused on grasses
Like modern capybara, extinct capybara were probably selective grazers, or mixed feeders, at times probably consuming more plant species than merely grasses.
Rear-most molars are tallest; capybaras chew most effectively in rear of mouth
(Koenigswald et al 1999)
High crowned teeth in capybara and other grazers, notes MacFadden (1997), have traditionally been assumed to have evolved along with development of widespread grasslands, but some researchers suggest grit from the soil drove this evolution.
New studies of a rare early mammal from Argentina suggest high crowned teeth didn't always evolve along with abrasive grasses; this trait appeared much earlier in some groups, before grasslands were major biomes world-wide.
Koenigswald et al 1999)
REPRODUCTION & DEVELOPMENT * *How do We Know This? Isotope studies of elements present fossil bones and tusks
about timing of reproductive stress, and timing of nursing.
Clues to stages of development come from tooth
replacement patterns and closure of sutures
in skull and limb bones.
No known studies
No known studies.
DISEASES AND PATHOLOGY*
*How do We Know This?Abnormalities in fossil bones may show
evidence of arthritis, cancer, nutritional stress, fractures and more.
No known studies.
Important Web Resources (including where to view fossils in museums):
San Diego Natural History Museum: Web site with major Pleistocene mammals (and fossils from other time periods) from California described and illustrated, including the capybara.The museum also exhibits several Pleistocene fossils, casts, and original models of Pleistocene animals together with seven original murals of Pleistocene plants and animals from southern California. Capybara are depicted in one mural interpreting the flora and fauna from Pleistocene sites excavated by the museum near Oceanside. The partial skull of this capybara is exhibited next to the mural.