''Octodon'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of octodontid

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

s native to

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

, in particular in the Chilean

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

. The best-known member is the

common degu The common degu (''Octodon degus''; ), or, historically, the degu, is a small hystricomorpha rodent endemic to the Chilean matorral ecoregion of central Chile. The name ''degu'' on its own indicates either the entire genus '' Octodon'' or, mor ...

, ''O. degus'', which is kept as a pet in various countries. Two of the four species of degus are

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

.Wise Geek
/ref>University of Michigan

Classification

This genus was first described in 1832 by the British zoologist Edward Turner Bennett.

Taxonomy

The genus name ''Octodon'' comes from the Latin ''octo'', eight, with reference to their teeth, molars and premolars having the shape of the number 8. The full list of species is: * ''O. bridgesii'', Bridges's degu, found in central Chile * ''O. degus'', the

or degu, found in central Chile * ''O. lunatus'', the moon-toothed degu, found in central Chile * ''O. pacificus'', the Pacific degu or Mocha Island degu, found exclusively on Mocha Island, Chile *''O. ricardojeda'', Ricardo Ojeda's degu, found in western

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

and

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

Distribution

In the wild, all species of degus live in the

, mainly in the mountains of

, to which most of them are

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

, aside from a few populations of '' O. ricardojeda'' in the neighboring province of

Neuquén Neuquén (; ) is the capital city of the Argentine province of Neuquén and of the Confluencia Department, located in the east of the province. It occupies a strip of land west of the confluence of the Limay and Neuquén rivers which form t ...

. They are found between 0 and 1,800 m in

altitude Altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum (geodesy), datum and a point or object. The exact definition and reference datum varies according to the context (e.g., aviation, geometr ...

Description

They are medium-sized octodontids. Their total body length varies between 200 and 390 mm, with a tail which measures between 81 and 170 mm and represents 70 to 80% of the head + body length. The coat color is grayish, or dull with orange highlights, and turns creamy yellow on the belly. The tail is carried slightly curved and is the same color as the body, and ends with a tuft of black hairs, with the extent of black depending on the species. The ears are quite large and protrude widely from the head, except in ''O. pacificus'' . The lower limbs are suitable for jumping, with pads on the soles of the paws that prevent slipping. The forelegs have four clawed fingers, along with a poorly developed fifth finger with a nail. The

glans The glans (, : glandes ; from the Latin word for "acorn") is a vascular structure located at the tip of the penis in male mammals or a homologous genital structure of the clitoris in female mammals. Structure The exterior structure of the g ...

of the

penis A penis (; : penises or penes) is a sex organ through which male and hermaphrodite animals expel semen during copulation (zoology), copulation, and through which male placental mammals and marsupials also Urination, urinate. The term ''pen ...

is characterized by a variable number of

spikes The SPIKES protocol is a method used in clinical medicine to break bad news to patients and families. As receiving bad news can cause distress and anxiety, clinicians need to deliver the news carefully. Using the SPIKES method for introducing and ...

, 5 or more in number, on each side.

Lifestyle

They are both

and diurnal. Degus are primarily folivorous herbivores. Their diet varies according to annual vegetation cycles. The consumption of their own droppings (

coprophagia Coprophagia ( ) or coprophagy ( ) is the consumption of feces. The word is derived from the Ancient Greek "feces" and "to eat". Coprophagy refers to many kinds of feces-eating, including eating feces of other species (heterospecifics), of o ...

) is practiced during times of scarcity. This provides them with a nutritional supplement thanks to the microbial fermentation that takes place in the

cecum The cecum ( caecum, ; plural ceca or caeca, ) is a pouch within the peritoneum that is considered to be the beginning of the large intestine. It is typically located on the right side of the body (the same side of the body as the appendix (a ...

and optimizes the digestion of fibrous foods. These social animals dig a burrow made of a series of tunnels where they live in small to large groups composed of both males and females.

Conservation status

'' O. bridgesii'' (assessed as conspecific with '' O. ricardojeda'') is considered vulnerable by the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

, while '' O. pacificus'' is considered

critically endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...

. The other two species are considered of

least concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

References

External links

* {{Taxonbar, from=Q628979 Rodent genera Taxa named by Edward Turner Bennett