# Mountain degu

The mountain degu (Octodontomys gliroides), also known as the Andean degu, is a species of rodent in the family Octodontidae. It is the only species in the genus Octodontomys. It is found in the foothills of the Andes in Argentina, Bolivia and Chile.

## Phylogeny

The phylogeny and placement of O. gliroides in relation to other octodontids was originally unclear. A study of mitochondrial DNA across the species' range published in 2016 solidified Octodontomys as a monophyletic group, albeit one with two distinct lineages, one of which is distributed across Bolivia and northern Chile, the other restricted to Argentina.
The following cladogram is adapted from Rivera et al., 2014:
Octodontidae :
Octodontidae
Octomys
Pipanacoctomys
Tympanoctomys
Octodontomys gliroides
Octodon
Spalacopus
Aconaemys porteri
Aconaemys fuscus
Aconaemys sagei :

## Description

The mountain degu is a moderate sized rodent with a length of 200 to 380 mm (8 to 15 in), including a tail of 100 to 190 mm (4 to 7 in), and a bodyweight in the range 100 to 200 grams (4 to 7 oz). The hairs are long and silky. The upper surface is greyish-brown, the chin is pure white, and the underparts are white with a grey base to the hairs. There is a tuft of white hair in front of the large ears, which are clad in short grey hair. The slender tail is bi-coloured (dark above and pale below) and has a tuft of brown or ochre hairs at the tip. Juveniles have darker fur above and greyer underparts. Their tails are brownish with a dark brown or black tufted tip.

## Distribution and habitat

This species is found in the mountainous areas of southwestern Bolivia, northwestern Argentina and northern Chile. It has a wide altitudinal range, occurring at 200 to 300 metres (660 to 980 ft) in Jujuy Province in Argentina, and at 4,400 metres (14,400 ft) in Potosí Department in Bolivia. The only species of octodontid found in the higher parts of its range, it inhabits dry rocky areas with tall cacti, shrubs and herbs.

## Behaviour

The mountain degu is a nocturnal, herbivorous rodent, being most active just after sunset. It does not have any special adaptations of skull or limbs for tunnelling, but digs short burrows and lives under rocks and in caves. Its tail can be autotomised, and it can be used as a prop when climbing. It is a sociable animal and communicates by means of a range of low, medium and high-pitched gurgles, twitters and squeaks, similar to the common degu and various species in genus Cavia. Social groups of the mountain degu range from 2 to 4 individuals that share a burrow system together to rest and hide from predators. Female mountain degus have a smaller home range than that of males.
The mountain degu feeds on the leaves and bark of shrubs, and on Acacia sheaths in the winter and on cactus fruits in the summer. It can obtain sufficient moisture from its food, particularly cactus, to satisfy its water requirements.
Mountain degu young in various stages of development have been found in November, and pregnant females and young in both January and May. A gestation period of 100-109 days has been reported with a litter size of one to three pups. The pups are precocial when born, already having their eyes open and being well-furred.

## Relationship with humans

The mountain degu is known to host parasites that are infectious to humans, such as the Chagas disease-causing Trypanosoma cruzi. It is also parasitized by bloodsucking fleas in genus Ectinorus and lice in the genera Ferrisella. Otherwise, it has little to no societal impact, similar to other degus.

## Conservation status

O. gliroides is listed as being of "least concern" by the International Union for Conservation of Nature because of its wide distribution, its presumed large population, its occurrence in some protected areas and apparent tolerance of some degree of habitat modification.