About Galea musteloides Meyen, 1833
Taxonomic Classification
The common yellow-toothed cavy, scientifically Galea musteloides Meyen 1833, is a rodent species in the family Caviidae, closely related to domesticated guinea pigs.
Karyotype and Dental Trait
It has a karyotype with 2n = 68 and FN = 136, and it has yellow teeth.
Species Distribution and Elevation Range
It is the most common and most widely distributed member of the genus Galea, found across Argentina, Bolivia, Chile, and Peru at elevations ranging from 20 to 5000 meters above sea level, with an overall range stretching from southern Peru to central Argentina.
Habitat Preferences
It occurs most often in moist areas including stream edges and croplands.
Recognized Subspecies
One recent study recognizes five subspecies of G. musteloides: boliviensis, demissa, leucoblephara, littoralis, and musteloides.
Subspecies Distinguishing Features
These subspecies are distinguished by differences in fur coloration, skull size and shape, auditory bullae size, and tooth shape.
Taxonomic Revision Note
Growing evidence suggests that the lowland form previously classified as G. musteloides is an independent species, which should be named G. leucoblephara.
General Behavioral and Ecological Traits
This species is described as a diurnal, group-living herbivore of squirrel size that occupies open habitats.
Birth Weight
At birth, male and female common yellow-toothed cavies have average weights of 36.4 g and 37.6 g respectively.
Reproductive Maturity
Individuals reach reproductive maturity between one and three months of age, with a recorded minimum breeding age of twenty-eight days.
Reproductive Cycle Parameters
Gestation lasts fifty-three days, lactation lasts three weeks, and average litter size is 2.7.
Interspecific Association in Peru
In Peru, G. musteloides sometimes associates with tuco-tucos of the genus Ctenomys; Galea individuals use tuco-tuco burrows and respond to tuco-tuco alarm calls, as documented by Sanborn and Pearson.
Captive Social Hierarchy
In captive groups, G. musteloides develops separate hierarchical social structures for males and females.
Captive Male Mating Behavior
Alpha males regularly guard receptive females, but this guarding has little effect: usually other males also mate with the same female, and over 80% of litters have multiple fathers.
Captive Female Mating Behavior
Females in captivity are clearly promiscuous, always mating with several males in the group.
Wild Social Structure Uncertainty
In the wild, the species is clearly territorial, but it remains unclear whether similar hierarchical social structures exist in natural populations, or whether wild G. musteloides live solitarily.
Adult Male Aggression Traits
Aggression between adult males occurs regularly.
Male Parental and Conspecific Behavior
Adult male G. musteloides never take part in parental care, and are aggressive toward subadult males even when the subadults are their own very young offspring.
Male-Female Interaction Trait
Males are not aggressive toward females.
Allonursing Behavior in Females
Adult females will lactate and nurse the offspring of other females during the first week of the offspring’s life, and nearly all offspring receive some milk from females other than their biological mother.
Maternal Care Preference
Females still preferentially care for their own offspring, and continue caring for their own offspring beyond the first week of life.
Genus Mating System Diversity
Closely related Galea species display a range of mating systems from monogamy to promiscuity, making the genus suitable for comparative studies.
Comparative Study Trends
Two general trends have been identified from this work: relative to body size, testis size is larger in promiscuous species; and higher social tolerance in captive groups is linked to greater promiscuity and higher testosterone levels in males.
Testosterone and Aggression Correlates
Testosterone levels and aggression levels in males are not correlated, and females consistently avoid males with higher than average aggression.
