The bunny rat, or hairy-soled conyrat (''Reithrodon auritus'') is a species of
rodent
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...
in the family
Cricetidae
The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, muskrats, and New World rats and mice. At almost 608 species, it is the second-largest family of mammals, and has m ...
, native to southern
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
.
Description
The bunny rat is a heavily built rat-like rodent, with a total length of , including the tail. Adults weigh an average of about . The body is covered in long soft hair, and the tail is also hairy, ending in a distinct tuft. The head is relatively large, with prominent rounded, hairy, ears. The hind legs are unusually long for a rat, with the first and fifth toes reduced in size, giving them an appearance similar to those of a rabbit. The fur is dark brown to buff-grey over the upper parts of the body, becoming paler, sometimes almost white, on the underparts. Without genetic analysis, the bunny rat can only be reliably distinguished from its close relative, the naked-soled conyrat, by the fact that the soles of its feet are hairy.
Its
karyotype
A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is disce ...
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
and eastern
Chile
Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...
south of about 36°S, and are found in a few patchy localities in northern Argentina and possibly parts of
Uruguay
Uruguay (; ), officially the Oriental Republic of Uruguay ( es, República Oriental del Uruguay), is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast; while bordering ...
. Bunny rats have also been reported from the
Falkland Islands
The Falkland Islands (; es, Islas Malvinas, link=no ) is an archipelago in the South Atlantic Ocean on the Patagonian Shelf. The principal islands are about east of South America's southern Patagonian coast and about from Cape Dubouzet ...
. Within this region, they are most commonly found in open grasslands such as
steppe
In physical geography, a steppe () is an ecoregion characterized by grassland plains without trees apart from those near rivers and lakes.
Steppe biomes may include:
* the montane grasslands and shrublands biome
* the temperate grasslands, ...
and
prairie
Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the ...
, but can also be found in shrublands, and even beech forest, below about . Four subspecies are currently recognised, although it is possible that the bunny rat represents a
species complex
In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...
, rather than a single species:
* ''Reithrodon auritus auritus'' - central Argentina
* ''Reithrodon auritus caurinus'' - northern Argentina
* ''Reithrodon auritus cuniculoides'' - southern Argentina, eastern Chile
* ''Reithrodon auritus pachycephalus'' -
Tierra del Fuego
Tierra del Fuego (, ; Spanish for "Land of the Fire", rarely also Fireland in English) is an archipelago off the southernmost tip of the South American mainland, across the Strait of Magellan. The archipelago consists of the main island, Isla G ...
Biology and behaviour
Bunny rats feed almost entirely on grass, and can consume a mass of vegetation equal to their own body weight in a single night. Although primarily nocturnal, they may also be active during the day, depending on the weather, and spend most of their waking hours feeding. They sleep in tunnels, which are about wide, and have multiple entrances. In many cases, they may co-opt tunnels dug by other rodent species, and may even share them with the original inhabitant.
Bunny rats can reach population densities of in ideal conditions. They are common prey for owls, and are thought to have a maximum lifespan of 15 months. They breed between September and March, but most commonly in the spring, and give birth to litters of up to eight pups. Females reach sexual maturity two months after birth, although this may be longer for males.