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The Degu (Octodon degus) is a small, caviomorph rodent that is native
to Chile. It is sometimes referred to as the Trumpet-tailed "Rat" (although not
related to the rat family) 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. 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 group have been shown to spontaneously nest comunally- 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, 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.
Degus are born relatively precocial, and their auditory and visual systems are functional at
birth. They are even born with a full coat of fur.
Unlike other octodontids, degus are diurnal, and they have good vision.
Their retinas include rod cells and two types of
cone cell, 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 environmental conditions, and like some other herbivores such as rabbits, they show coprophagy, chewing their
own feces so as to extract more nutrition from them. This also servs to maintain healthy
gut function during times when food is scarce. 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. However,
numbers of all species of degu have been declining over recent decades, most likely due to human disturbance.
Degus are prone to diabetes due to their divergent insulin stucture. For this reason, are used frequently for research in this field. this is in fact why degus
became pets, as animals were imported into various countries for research and study.
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, bubbly personality, the haired tail (as
compared to rats) and their lifetime: they are said to live up to 13 years under ideal circumstances (although a poor gene
pool/genetic background often reduces a pet degu's lifespan significantly).
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.
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