Santa Catarina's guinea pig (''Cavia intermedia'') or Moleques do Sul cavy is a rare
guinea pig
The guinea pig or domestic guinea pig (''Cavia porcellus''), also known as the cavy or domestic cavy (), is a species of rodent belonging to the genus '' Cavia'' in the family Caviidae. Breeders tend to use the word ''cavy'' to describe the ...
species
In biology, a species is the basic unit of 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 the appropriate s ...
of southeastern
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 sout ...
.
Distribution
The small mammal is
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...
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 . ''Cavia intermedia'' is phylogenetically comparable, and said to be a common ancestor of the species ''
Cavia magna
The greater guinea pig (''Cavia magna'') is a species of rodent found in the coastal strip of Brazil and Uruguay, where it lives in moist grassland and marshes.
Description
A large rodent, the greater guinea pig grows to a total length of and w ...
'', who also inhabited the island. The guinea pig's geographical distribution of only 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.
Physical description
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.
Habitat and diet
On the island are about 31 species of birds, an undescribed worm from the family
Amphisbaenidae
The Amphisbaenidae (common name: worm lizards) are a family of amphisbaenians, a group of limbless vertebrates.
Geographic range
Amphisbaenids occur in South America, some Caribbean islands, Europe, and sub-Saharan Africa.
Taxonomy
One deep- ...
. 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
''Paspalum vaginatum'' is a species of grass known by many names, including seashore paspalum, biscuit grass, saltwater couch, silt grass, and swamp couch.Stenotaphrum secundatum'', while it only amounts to 0.77 ha of land. Bushes and grasses such as ''
Cortaderia selloana
''Cortaderia selloana'' is a species of flowering plant in the Poaceae family. It is referred to by the common name pampas grass, and is native to southern South America, including the Pampas region after which it is named.
Etymology
''Cortade ...
'' and '' Verbesina glabrata'' surround the grazing grounds and supply protection and shelter to these insular cavies.
Predators and ectoparasites
Predators of the ''Cavia Intermedia'' are mostly raptors, such as southern caracaras ('' Caracara plancus''), Yellow headed caracaras ('' Milvago chimachima''), and the Chimango caracaras ('' Milvago chimango''). Moleques do Sul guinea pigs are also vulnerable to the burrowing owl and periguine falcon, which were not observed over the course of research.
Cavies are reported to experience 50 different ectoparasites, however only 4 species have been observed on ''C.intermedia''; two louse: '' Gliricola lindolphoi'' (
Amblycera
The Amblycera are a large clade of chewing lice,
parasitic on both birds and mammals. The Amblycera are considered the most primitive clade of lice.
Description
These insects are very much like the familiar advanced sucking lice, except t ...
Amblycera
The Amblycera are a large clade of chewing lice,
parasitic on both birds and mammals. The Amblycera are considered the most primitive clade of lice.
Description
These insects are very much like the familiar advanced sucking lice, except t ...
Amblycera
The Amblycera are a large clade of chewing lice,
parasitic on both birds and mammals. The Amblycera are considered the most primitive clade of lice.
Description
These insects are very much like the familiar advanced sucking lice, except t ...
:
Trombiculidae
Trombiculidae (); commonly referred to in North America as chiggers and in Britain as harvest mites, but also known as berry bugs, bush-mites, red bugs or scrub-itch mites, are a family of mites. Chiggers are often confused with jiggers – a t ...
Acari
Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear evid ...
:
Trombiculidae
Trombiculidae (); commonly referred to in North America as chiggers and in Britain as harvest mites, but also known as berry bugs, bush-mites, red bugs or scrub-itch mites, are a family of mites. Chiggers are often confused with jiggers – a t ...
). The mite species were located on the ears of the observed cavies. The relative abundance on ''C. intermedia'' was 33 louse species per cavy. Observations suggest the ectoparasite/host ratio of ''C. intermedia'' is higher than other ''Cavia'' species. ''C. amperea'' findings show a 23 louse parasites/host ratio and on ''C. porcellus'' there is a 29.1 parasites/host ratio. The higher ratio is related to high population density corresponding to direct contact between the insular cavies, allowing mites and louse species to spread to nearby hosts.
Life stages and reproduction
''C. intermedia'' can reproduce year around, with a gestation time of about 60 days. When compared to domesticated cavies and '' C. magna'', the weaning of young is expected to be no longer than a 30-day weaning period.
These endemic cavies have been recorded to produce 1-2 young a litter, which is the same as their relative ''C. magna'' who also produces 1-2 young a litter.
These insular guinea pigs have a much slower maturation rate than other cavies.
Researchers observed 4 distinct classes within ''C. intermedia'' by distinguishing ossified sutures; Age 1 is classified as young without any ossified sutures, Age 2 is classified as 1 ossified suture ranging <400grams, Age 3 is classified as a subadult missing one ossified suture and weighing 400-500g, Age 4 is classified as an adult with all three ossified sutures weighing over 500grams.
From age 1 individuals vary from 100g-150g when not bred in captivity (99g). The highest recorded age 1 cavy was 200g.
The lowest recorded mass for the adult Age 3 or 4 was 495g. Adult cavies have a mass greater than 500g.
In comparison to other species of ''
Cavia
''Cavia'' is a genus in the subfamily Caviinae that contains the rodents commonly known as guinea pigs or cavies. The best-known species in this genus is the domestic guinea pig, ''Cavia porcellus'', a meat animal in South America and a common ...
'', ''C. intermedia'' offspring can experience the highest ratio of offspring average mass to mother's average mass. The offspring can reach up to 24% of the mothers average mass.
Although the mass differences between sexes had no significance shown in the data, this is not normal for other cavy species. The male guinea pigs usually have higher masses.
The lifespan of these cavies is not well known due to limited data and lack of research; however Moleques do Sul guinea pigs had an average monthly survival rate of (0.81) which is high for a species within a small geographic location.
Behaviors
''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
''Cavia'' is a genus in the subfamily Caviinae that contains the rodents commonly known as guinea pigs or cavies. The best-known species in this genus is the domestic guinea pig, ''Cavia porcellus'', a meat animal in South America and a common ...
'' species due to similar home-range sizes.
Threats and conservation
Because of the species low population size and small geographic location, ''C. intermedia'' is considered Critically Endangered. Since October 2021, ''C. intermedia'' has been classified as Largely Depleted by the IUCN.
Within the grazing grounds the guinea pigs left evidence of exploitation of their food sources. Grasslands on the surrounding islands have a higher biomass and reach about 50 cm, however in feeding areas of the cavies the grasses only reach 5 cm high. Due to the cavies small feeding patch of 0.77 ha overexploitation when the population density is higher creates a natural fluctuation in the mortality of the species. If the land were to experience disturbances or environmental stochastic events the species could more severely decline. Although the site is within a Preservation area, restricted entry is not enforced. Implementation of land management and active monitoring may protect the species from other possible anthropogenic or natural threats.
Researchers suggest monitoring the species vulnerability to parasites and subject the species to parasitological and immunological assessments.
Invasive species of lice, mites or grasses entering the system is a potential threat to the population.