Degu (Octodon degus)

Mar 30, 2014 Features / Columnists, Interesting Creatures in Guyana

The degu (Octodon degus) is a small caviomorph rodent that is endemic to the matorral ecoregion of central Chile. It is sometimes referred to as the brush-tailed rat, and is also called the common degu, to distinguish it from the other members of the genus Octodon. Other members are also called degus, but they are distinguished by additional names.
The name “degu” on its own, however, indicates either the genus Octodon or, more usually, O. degus. Degus are in the parvorder Caviomorpha of the infraorder Hystricognathi, along with the chinchilla and guinea pig. The word degu comes from the Mapudungun dewü (mouse, rat).

Degu

The degu is a small animal with a body length of 25.0 to 31.0 centimetres (9.8–12.2 in) and a weight of 170 to 300 grams (6.0 to 10.6 oz).
It has yellow-brown fur above and creamy-yellow below, with yellow around the eyes and a paler band around the neck. It has a long, thin tail with a tufted black tip, dark sparsely-furred ears, and pale grey toes. Its fifth toe is small with a nail, rather than a claw, on the forefeet. Its hind feet are bristled. Its cheek teeth are shaped like figures-of-eight, hence the degu’s genus name “Octodon”.
Degus are highly social. They live in burrows, and, by digging communally, they are able to construct larger and more elaborate burrows than they could on their own. Degus digging together coordinate their activities, forming digging chains. Females living in the same group have been shown to spontaneously nest communally; they nurse one another’s young. They spend a large amount of time on the surface, where they forage for food. When foraging, their ability to detect predators is increased in larger groups, and each animal needs to spend less time in vigilance.
Degus exhibit a wide array of communication techniques. They have an elaborate vocal repertoire comprising up to 15 unique sounds, and the young need to be able to hear their mother’s calls if the emotional systems in their brains are to develop properly. They use their urine to scent mark, and experiments have shown that they react to one another’s marks, although in males the hormone testosterone may suppress their sense of smell somewhat.
Female degus are pregnant for approximately 90 days, having a comparatively long gestation period compared to other non-caviomorph rodents.
Female pregnant weight varies over the course of gestation and according to litter size; litters contain an average of six pups, but size can range from one or two up to 12 young.
Degu pups are born relatively precocial, fully furred and with eyes open and their auditory and visual systems are functional at birth. Unlike most other rodents, male degus also take part in protecting and raising their pups until they are old enough to leave the family.
Unlike, also, some other octodontids, degus are diurnal (active during the day), and they have good vision. Their retinas include rod cells and two types of cone cells, corresponding to peak sensitivity in the green and ultraviolet regions of the spectrum.
Behavioural experiments have shown that degus are able to discriminate ultraviolet light from the wavelengths visible to humans; it is likely that this ultraviolet sensitivity has a social function, since both their ventral (stomach) fur and their urine are highly UV reflective.
Degus are strictly herbivorous, in the wild feeding on grasses and browsing the leaves of shrubs, though they will also take seeds. Throughout much of the year forage is dried and so degus are specially adapted to a very high fibre intake, and this varies between food types and environmental conditions.
Like some other herbivores such as rabbits, they perform coprophagy (faecal reingestion) so as to extract more nutrition from their diet. This also serves to maintain healthy gut function during times when food is scarce.
Perhaps the most remarkable feature of degu physiology is their intolerance of dietary sugar. Degus have been found to have a divergent insulin structure (one of the hormones that regulate blood glucose level) and so are highly susceptible to developing diabetes mellitus when fed regularly on a diet containing free sugars.
This is thought to be due to evolutionary pressure arising from the lack of availability of free sugars in the degu’s natural environment.
Degus need regular sand baths to keep their coats healthy and free from grease. They should have access to this regularly, preferably two or three times a week, half an hour at a time. Daily sand bathing can however make their coats soiled.
(Source: Wikipedia – The Free Online Encyclopedia)