Santa Catarina's guinea pig (Cavia intermedia ) or Moleques do Sul cavy is a rare guinea pig species of southeastern South America.
The Cavia intermedia is a rodent approximately 20–40 cm in length. These cavies lack sexual dimorphism, which differs from other cavies, because males are usually larger than females. Their cylindrical body shapes are in shades of brown or gray and are carried by short limbs. These guinea pigs have coarse, long fur and longer fur in the neck region, with ears having no fur. These guinea pigs, like most, have no external tail. Cavies have incisors that continuously grow and are naturally filed down by grazing habits.
The small mammal is endemic to the small coastal island of Moleques do Sul Archipelago, located in the state of Santa Catarina in southern Brazil. The archipelago formed about 8,000 years ago, having a total of three islands with a surface area of only 10.5 hectares (26 acres). Cavia intermedia is phylogenetically comparable, and said to be a common ancestor of the species Cavia magna, who also inhabited the island. The guinea pig's geographical distribution of only 4 hectares (9.9 acres) is one of the world's smallest for a mammal. The region is a part of Serra do Tabuleiro State Park where restrictions and protection of the species are not enforced. When population densities were estimated, two techniques were used, one was determined using trapping grids, which is usually placed in optimum habitat, which would be only 0.77ha, which are their feeding grounds. This first estimate is 28-44cavies/ha, which is believed to be an overestimate. The other method was minimum-number-known-alive (MNKA), covering the 6.34 ha of vegetation used by the cavies known due to sited feces.
On the island are about 31 species of birds, an undescribed worm from the family Amphisbaenidae. The climate of Southern Brazil is humid, with hot summers and rainfall all throughout the year. The rainfall is reduced in winter seasons.
The Moleques do Sul guinea pigs are found in 6.34 ha area covered with herbaceous vegetation that serves as a stable food source, Paspalum vaginatum and Stenotaphrum secundatum, while it only amounts to 0.77 ha of land. Bushes and grasses such as Cortaderia selloana and Verbesina glabrata surround the grazing grounds and supply protection and shelter to these insular cavies.
Cavia intermedia has an equal male to female ratio within the population, but also home-range sizes do not change with male or female population sizes. Other cavies such as C. magna and C. aperea have significant home-range data suggesting that males home ranges are larger than females, while C. intermedia have home ranges of averaging 1,700 m^2 for both male and female cavies. Communication and socialization is assumed different in C. intermedia populations than with C. magna and other Cavia species due to similar home-range sizes.
