Greater guinea pig
|Greater guinea pig|
Ximenez et al., 1980 
A large rodent, the greater guinea pig grows to a total length of 310 mm (12.2 in) and weight of 636 g (22.4 oz) for males and a total length of 303 mm (11.9 in) and weight of 537 g (18.9 oz) for females. The dorsal fur is dark agouti brown and the underparts are reddish-brown. It is semiaquatic and has membranes joining the toes.
Distribution and habitat
The greater guinea pig is a herbivore. It is a solitary animal and has a complex network of tunnels and runways through the vegetation. The home range is variable and seems to be related to the animal's size, its sex, and the water level in the area. Females seem capable of breeding at any time of year but births predominate in spring and the early part of summer. Females may have three litters in the year. The gestation period is about 64 days and the litter size is very small (1 or 2 pups). The young are quite large when born and grow fast, and some females born in the spring, themselves breed successfully when between 30 and 45 days old. This small mammal is unusual in that it produces a small number of precocial offspring with a high survival rate when it might have been expected to produce large litters of altricial young.
The International Union for Conservation of Nature has rated the conservation status of the greater guinea pig as being of "least concern". It has a restricted range but has a total area of occupancy of more than 20,000 square kilometres (7,722 sq mi). It is believed to have a large total population, and although the population is thought to be declining slightly in Uruguay, this is not at a rate sufficiently significant for it to be listed in a more threatened category.
- Gonzalez, E. & Lessa, E. (2008). "Cavia magna". IUCN Red List of Threatened Species. Version 2014.2. International Union for Conservation of Nature. Retrieved 11 August 2015.
- Woods, C.A.; Kilpatrick, C.W. (2005). "Infraorder Hystricognathi". In Wilson, D.E.; Reeder, D.M. Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 1553. ISBN 978-0-8018-8221-0. OCLC 62265494.
- John F. Eisenberg; Kent H. Redford (15 May 2000). Mammals of the Neotropics, Volume 3: Ecuador, Bolivia, Brazil. University of Chicago Press. p. 456. ISBN 978-0-226-19542-1.
- James L. Patton; Ulyses F. J. Pardiñas; Guillermo D’Elía (2015). Mammals of South America, Volume 2: Rodents. University of Chicago Press. pp. 699–. ISBN 978-0-226-16960-6.
- Kraus, C. et al. 2005. Living slow and dying young? Life-history strategy and age-specific survival rates in a precocial small mammal. In: Journal of Animal Ecology 74:171–180