Degu
Scientific classification
Domain:Eukaryota
Kingdom:Animalia
Phylum:Chordata
Class:Mammalia
Order:Rodentia
Family:Octodontidae
Genus:Octodon
species:degus
Binomial name
Octodon degus
The Degu (Octodon degus) or Trumpet-tailed Rat is a small rodent that is native to Chile. It is sometimes also called the Common Degu, to distinguish it from the other members of the genus Octodon. These are also called degus, but they are distinguished by additional names. They are:
  • O. bridgesi, Bridge's Degu, found in Argentina
  • O. lunatus, the Moon-toothed Degu, a nocturnal animal found in northern Chile
  • O. pacificus, the Mocha Island Degu, a recently discovered species that is found only on Isla Mocha, a small coastal island in the Valdivian rainforest zone of central Chile. It has long, soft fur, and a long, poorly tufted tail; these are thought to be primitive features in degus

The name "degu" on its own, however, indicates either the genus Octodon or, more usually, O. degus.

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 co-ordinate their activites, forming digging chains. Females living in the same burrow have been shown to nurse one another's young. When foraging, their ability to detect predators is increased when they are in larger groups, and each animal needs to spend less time in vigilance. They have an elaborate vocal repertory, 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 degus are born in burrows, they are precocial, and their auditory and visual systems are functional at birth.

Unlike other octodontids, degus are diurnal, and they have good vision. Their retinas include rod cells and two types of cone, one of which has its peak sensitivity in the ultraviolet region of the spectrum. Behavioral 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 herbivores, feeding on grasses and browsing the leaves of shrubs, though they will also take seeds. Their feeding rate is constrained by the rate at which they can digest this relatively low quality food, and this varies between food types and conditions, and like some other herbivores such as rabbits, they show coprophagy, chewing their own feces so as to extract more nutrition from them. Although they are active by day, in high summer they do not leave their burrows in the middle of the day, and in hot conditions they forage as quickly as possible instead of maximising the quality of their food. They tend to forage in shaded areas, though this tendency is reduced in the absence of predators. In open areas they spend more time being vigilant, so their effectiveness as foragers is reduced. Degus have a significant impact on the vegetation in areas where they live, and as the only rodent foraging by day, their numbers influence on the food supply available to the more numerous nocturnal rodents.

Degus are diabetic by birth, and thus they were and are used frequently for research in this field.

Degus have become popular as pets, though until very recently they were seldom found in pet shops. Their advantages over traditional small pets are their diurnal habits, the haired tail (as compared to rats) and their lifetime: they are said to live up to 13 years under ideal circumstances. More information about degus and how to take care of them can nowadays be found in the Internet, as there are very few books on the matter.

External links

References

  • Bacigalupe, L. D., Rezende, E. L., Kenagy, G. J., & Bozinovic, F. (2003). Activity and space use by degus: a trade-off between thermal conditions and food availability? Journal of Mammalogy, 84, 311-318.
  • Bozinovic, E., & Vasquez, R. A. (1999). Patch use in a diurnal rodent: handling and searching under thermoregulatory costs. Functional Ecology, 13, 602-610.
  • Bozinovic, F., & Torres-Contreras, H. (1998). Does digestion rate affect diet selection? A study in Octodon degus, a generalist herbivorous rodent. Acta Theriologica, 43, 205-212.
  • Ebensperger, L. A., & Bozinovic, F. (2000). Communal burrowing in the hystricognath rodent, Octodon degus: a benefit of sociality? Behavioral Ecology and Sociobiology, 47, 365-369.
  • Ebensperger, L. A., & Caiozzi, A. (2002). Male degus, Octodon degus, modify their dustbathing behavior in response to social familiarity of previous dustbathing marks. Revista Chilena De Historia Natural, 75, 157-163.
  • Ebensperger, L. A., Veloso, C., & Wallem, P. K. (2002). Do female degus communally nest and nurse their pups? Journal of Ethology, 20, 143-146.
  • Ebensperger, L. A., & Wallem, P. K. (2002). Grouping increases the ability of the social rodent, Octodon degus, to detect predators when using exposed microhabitats. Oikos, 98, 491-497.
  • Gutierrez, J. R., Meserve, P. L., Herrera, S., Contreras, L. C., & Jaksic, F. M. (1997). Effects of small mammals and vertebrate predators on vegetation in the Chilean semiarid zone. Oecologia, 109, 398-406.
  • Helmeke, C., Poeggel, G., & Braun, K. (2001). Differential emotional experience induces elevated spine densities on basal dendrites of pyramidal neurons in the anterior cingulate cortex of Octodon degus. Neuroscience, 104, 927-931.
  • Jacobs, G. H., Calderone, J. B., Fenwick, J. A., Krogh, K., & Williams, G. A. (2003). Visual adaptations in a diurnal rodent, Octodon degus. Journal of Comparative Physiology A: Neuroethology Sensory Neural and Behavioral Physiology, 189, 347-361.
  • Kenagy, G. J., Veloso, C., & Bozinovic, F. (1999). Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy. Physiological and Biochemical Zoology, 72, 78-86.
  • Lagos, V. O., Contreras, L. C., Meserve, P. L., Gutierrez, J. R., & Jaksic, F. M (1995). Effects of predation risk on space use by small mammals: a field experiment with a neotropical rodent. Oikos, 74, 259-264.
  • Ovtscharoff, W., & Braun, K. (2001). Maternal separation and social isolation modulate the postnatal development of synaptic composition in the infralimbic cortex of Octodon degus. Neuroscience, 104, 33-40.
  • Vasquez, R. A., Ebensperger, L. A., & Bozinovic, F. (2002). The influence of habitat on travel speed, intermittent locomotion, and vigilance in a diurnal rodent. Behavioral Ecology, 13, 182-187.
  • Yunger, J. A., Meserve, P. L., & Gutierrez, J. R. (2002). Small-mammal foraging behavior: mechanisms for coexistence and implication for population dynamics. Ecological Monographs, 72, 561-577.
  • Ziabreva, I., Schnabel, R., Poeggel, G., & Braun, K. (2003). Mother's voice "buffers" separation-induced receptor changes in the prefrontal cortex of Octodon degus. Neuroscience, 119, 433-441.