Spix's yellow-toothed cavy (''Galea spixii'') is a

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are roden ...

, a

cavy Caviidae, the cavy family, is composed of rodents native to South America and includes the domestic guinea pig, wild cavies, and the largest living rodent, the capybara. They are found across South America in open areas from moist savanna to tho ...

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

from

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

. It is found in

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

east of the

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

and much of south central to northeastern

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

. The species is found in open

savanna A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to ...

and

semiarid A semi-arid climate, semi-desert climate, or steppe climate is a dry climate sub-type. It is located on regions that receive precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of semi-ar ...

habitats, such as the

Cerrado The ''Cerrado'' (, ) is a vast ecoregion of tropical savanna in eastern Brazil, particularly in the states of Goiás, Mato Grosso do Sul, Mato Grosso, Tocantins, Minas Gerais, and the Federal District. The core areas of the Cerrado biome are ...

and

Caatinga Caatinga (, ) is a type of semi-arid tropical vegetation, and an ecoregion characterized by this vegetation in interior northeastern Brazil. The name "Caatinga" is a Tupi word meaning "white forest" or "white vegetation" (''caa'' = forest, v ...

of Brazil. Its

karyotype A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is disce ...

is 2n = 64 and FN = 118. ''Galea spixii'' and ''G. musteloides'' are similar and may actually be the same species. ''G. spixii'' tolerates a wide range of environmental changes, though they need open habitats. It is the most stable species within the ''Galea'' group because it is extremely abundant throughout its range. Gestation is about fifty days. Litter size ranges from one to five, with an average of three. They have hair and open eyes at birth. Maturation of the two sexes takes differently long: female ''G. spixii'' have an open vagina when they are approximately eighty days old while the testicular descent is completed in male ''G. spixii'' at around one hundred thirty-five days old. Males and females in this species are aggressive to each other. Paternal care is rarely remarkable. When females go into estrus aggressiveness increases. On the other hand, when male approaches females in order to mate, it competes aggressively with other males. A study done in Brazil reported that nine male cavies were put to death to experiment their sperm recovery by soaking or injecting their sperm into a liquid that contained a chemical buffer. Unfortunately, there were no distinctive results between either soaking or injecting.da Silva et al.(2016) Characterization of epididymal sperm from Spix's yellow‐toothed cavies (Galea spixii Wagler, 1831) recovered by different methods.''Acta Zoologica (Stockholm) 98'': 285– 291.

References

Cavies Mammals of Bolivia Mammals of Brazil Mammals described in 1831 {{rodent-stub