The Unique Rodents of South America
Just as Australia has a number of rather unusual native animals, I was intrigued by those of South America. I have seen very few photos and even less information about some of these fascinating creatures. This article will focus on some of the rodents which are endemic to the continent.
In taxonomic terms, one of the orders in the class Mammalia is the Rodents. Further down the line, eighteen 'families' split into caviomorpha and phiomorpha. The former are mostly native to South America with a few found in North America while the latter belong to the Old World.
The most easily recognised rodent of the South American rodents (to a non-South American) is the cavy or guinea pig. The genus Cavia has a number of species only one of which is the domestic guinea pig, The guinea pig is an important meat animal in the various South American countries.
The capybara is the largest rodent in the world reaching a length of some 107 to 134 cm, a height of 50 to 64 cm and a weight of 35 to 66 kg. The semi-aquatic capybara is found throughout South America apart from the west coast areas. It has a single coat and the hindquarters are taller than the forequarters. The paws are slightly webbed.
The agouti species belong to the genus Dasyprocta and grows to a length of 51 cm and weighs around 4 kgs. The fur is a brown with lighter underparts. The coat is glossy with orange overtones and has given rise to 'agouti' becoming a term describing fur of similar colour on other animals such as the guinea pig.
The paca is sometimes classified with the agouti, depending on the authority consulted. It is considered a luxury food source by the people of Guyana and Mexico. In Trinidad, there is a high level of poaching with the flesh of the paca being sold at high prices. It was once to HRH Queen Elizabeth II thus resulting the nickname 'royal rat'. It is called majas in the Peruvian Amazon.
The acouchis is generally smaller than the common agouti and has a very short tail. It is sometimes called the tailed agouti. There are two species (some sites say there may be more) – the red and green, believe it or not. The colouration of the two differs, being brown or greenish with bright orange or red markings on the head. They are diurnal and feed on fruit.
The pacarana is large for a rodent and is also rare, slow-moving and nocturnal. It has a superficial similarity to the paca. It is a monotypic species being the only member of the family Dinomyidae. It has a chunky body and weighs up to 15 kg and is 79 cm in length. The thick, furry tail adds a few more centimetres.
The degu is endemic to central Chile. Its taxonomic name is Octodon degus and its common names include brush-tailed rat or common degu to distinguish it from other 'Octodons'. Octodons have cheek teeth which are shaped like figures-of-eight. It is a small rodent just 25 to 31 cm long and 170 to 300 grams in weight. The pelage is yellow-brown on the upper surfaces and more creamy underneath. There are yellow eye-rings and a pale band around the neck. The long thin tail has a black tuft at the end. The toes are pale and grey with the fifth toe on the forefoot having a nail rather than a claw. The hindfeet are bristled.
The tucotuco (Ctenomys spp) has short legs but is heavily built. The pelt is loose on the body. The forefeet are long for burrowing and the hind feet bristled for grooming. Small ears sit atop large heads. The tail is hairy. Size ranges from 15 to 25 cm in length and up to 700 grams in weight.
There are two species of mara, the Patagonian (Dolichotis patagonum) and the Chacoan (Dolichotis salinicola). They have stocky bodies with three toes on the hind feet and four on the forefeet. They resemble long-legged rabbits and can run at 29 kph. They weigh over 11 kg as adults. Most have brown heads and bodies, a dark rump with a white fringe round the base and a white stomach.
Most spiny rats resemble rats despite being closer to guinea pigs and chinchillas. They are found from central Central America through most of South America. Many of this genus can release their tails if they are attacked. This confuses the predator long enough for the rat to escape. However its tail does not regenerate. Most species are rare. There are arboreal and terrestrial species but nearly all are found near abundant water and are herbivorous.
Nutria or Coypu (above)
Also known as the river rat, this is a large, herbivorous, semi-aquatic rodent and a monotypic species. The coypu has been introduced to North America, Africa, Asia and Europe for commercial fur production. However, in most cases its feeding and burrowing behaviours have made it an invasive pest. Coypus waste 90% of the plant material they chew off.
Hutias inhabit the Caribbean Islands and have a length of 21 to 46 cm and a weight of 2.8 to 8.5 kg. There are a number of species, some of which have tails. These vary from vestigial to prehensile. The bodies are stout and the head large. They nest in trees or rock crevices. In Cuba, they are eaten by local people. All but two species are considered threatened. The Desmarest hutia has banana-shaped faeces leading to its common name of 'banana rat'.
Chinchillas are crepuscular and native to the Andes. They live at altitudes up to 15,000 feet. It is named after the Andean tribe, the Chincha, who used its dense, velvet-like fur for clothing. Most modern chinchilla fur is from farm-raised animals.
Viscachas look like rabbits with a nicely curled tail. There are five species. They have bushy tails and long, furry ears.
The Plains variety is distinguished by its black and grey moustache-like markings. It lives in large colonies but separated into family units. It is very vocal. Because it can strip grasslands which are intended for grazing, ranchers have long considered it a pest species.
The northern variety is grey or brown with lighter under parts. Its harsh, rocky environment has led to a very varied diet with the animal eating whatever it can find. The southern (mountain) viscacha is more red.
There are nine known species of chinchilla rat. Although they resemble chinchillas, they are more like a short-tailed rat. They have soft, silvery-grey fur. Stiff hairs cover the three middle digits of the rear paws. They have a massive skull which narrows down at the face.
Prehensile-tailed porcupine (above)
The prehensile-tailed porcupines are arboreal and have a prehensile tail which is devoid of spines. All four paws are modified for grasping, making them adept climbers. They feed on leaves, fruit bark, roots, buds and shoots. They are slow-moving and roll into a ball if threatened. The babies are born with soft hair which hardens to quills as they mature. There are only four toes on the hind paws which have a fleshy pad on the inner side. The pad acts as a hand as the animal can grasp objects between the pad and the toes.
Just as South America has a number of distinctive rodents, so it has a number of mammals, birds, insects and reptiles many of which are unique and equally fascinating.