| Microlivestock - Little-Known Small Animals with a Promising Economic Future |
|Part IV : Rodents|
The capybara (Hydrochoerus hydrochaeris), the world's largest rodent, can be as big as a sheep and weigh as much as a small person. Its natural habitat is the environs of South America's rivers, marshlands, and swamps, where it feeds on the grasses and reeds that grow near water.1
Because of its size, tasty meat, valuable leather, and rapid reproduction, the capybara is a candidate for both ranching and intensive husbandry throughout the hot and humid lowland tropical regions of Latin America. It seems easy to handle. It is commonly raised in zoos or occasionally as a pet, and has, in at least one instance, been proven successful in large commercial herds.
In floodplain ecosystems, capybaras complement cattle because they prefer to graze swamp grasses rather than the dryland grasses on which cattle feed. They have simple stomachs, but are one of the more efficient herbivores. Although they are "selective feeders" that eat lush waterside grasses "preserved in quality" by the water, they also graze pasture, usually selecting new growth that is often too short and scattered for cattle, with their large muzzles, to eat.
AREA OF POTENTIAL USE
The floodplains of the South American subtropics and tropics where the animal is indigenous.
APPEARANCE AND SIZE
Although they have blunt, horselike heads, capybaras look like gigantic guinea pigs. They are ponderous, barrel shaped, and have a tail too small to be seen from a distance. Their skin is tough and covered by sparse, bristlelike hairs: the color above is reddish brown to gray; beneath, it is yellowish brown.
The front legs are shorter than the back. Slightly webbed toes - four on the front feet and three on the back - make them good swimmers. They dive with ease and can stay underwater for up to five minutes. They also move nimbly on land.
The capybara is extremely large for a rodent. In size and color, it looks much like a pig. Often more than 100 cm long and 50 cm high at the shoulder, it can exceed 50 kg liveweight. Indeed, specimens weighing up to 90 kg have been reported.
Before livestock were introduced, the capybara grazed widely over riverine regions throughout South and Central America. Today, it is found in the flooded grasslands from Panama to Paraguay. Mainly, it occurs in the watersheds of the Orinoco, Amazon, Paraguay, and Parana rivers. High population densities exist in the Pantanal of western Brazil and on the Llanos floodplains of Venezuela and Colombia.
There are few precise population counts, but capybaras can occur in large numbers.2 However, in many areas they appear to be on the verge of extinction, being deliberately eradicated by farmers who think they compete with cattle and transmit diseases. Also, in some areas illegal hunting goes on year-round and great numbers are killed. The animals are particularly vulnerable during the dry season, when they concentrate around the diminished river channels and water holes.
HABITAT AND ENVIRONMENT
As noted, most capybaras live in swampy or grassy areas bordering rivers. However, some are found in other habitats, ranging from open plains to tropical rainforests. But even here they stay near ponds, lakes, streams, and swamps, and never venture much more than 500 m from water.
The capybara, like all rodents, is a simple-stomached animal, but it is a true herbivore. Its digestive system is especially adapted for fibrous materials. The large cecum - the site of enzymatic digestion— serves a function like that of the rumen of sheep, cattle, and goats. It has a digestive capacity similar to that of a sheep's rumen.
Like rabbits and all the rodents, capybaras are coprophagous. That is, during the morning hours when they are resting, soft feces from the cecum are passed a second time through the digestive system.3
Contributing to the animal's digestive ability is its efficient mastication. It chews its forage seemingly incessantly, reducing it to extremely small particles before it is swallowed.
Under natural conditions, the females annually bear 1 or 2 litters, each averaging from 4 to 6 offspring. Birth weight is between 1 and 2 kg, depending on litter size and sex. Both males and females reach sexual maturity when they reach a liveweight of 30 kg or more— usually between the first and second year of life.
Capybaras are intelligent, shy, inoffensive, and harmless. In undisturbed ecosystems, they are gregarious and live in family groups of up to 30. The young follow the mother about for many months after birth.
Unlike most rodents, they do not construct dens, but the groups have specific resting areas.
The animals are both diurnal and nocturnal and, like many herbivores, they graze at daybreak and dusk, and perhaps also at midnight. They spend the morning resting in weeds on riverbanks, and at noon they cool off by bathing for an hour or so before grazing. They may feed belly deep in water.
Capybaras wallow in mud, allowing it to dry on their skin before bathing again. Mange can develop in captivity when they cannot take a mud bath.
When startled, a capybara barks loudly and dashes away, but after running 200 m or so it tires, slows down, and may lapse into hyperthermia. At that point a hunter can easily catch it. However, if the animal reaches water, it usually eludes the pursuer because it swims so well - especially underwater.
Capybara meat is white and has qualities and properties (such as high emulsification) that might allow it to compete with pork and other meats in the food industry. Spanish-style sausages, Italian-style mortadellas, frankfurters, and German-style smoked chops have been produced experimentally.4 However, at present, the meat is mainly consumed only in the dried and salted form. It is particularly popular in Venezuela, where more than 400 tons are sold every year, especially during Easter festivities.5
The capybara's hide is one of the best for glove making. This luxury product, known in international commerce as carpincho leather, fetches high prices on European markets because it is more heat resistant than most leathers and because it stretches in only one direction. This one way grain allows gloves to stretch sideways without lengthening and looking sloppy.
The capybara appears suitable for raising as a livestock animal. Amerindians traditionally collected capybara orphans during the hunting season and raised them until needed for food. Capybara breeding was reported in Brazil as early as 1565.
Modern attempts have been made towards domestication. Researchers at the Institute of Animal Production in Venezuela, for instance, started a breeding program in the 1970s using 20 females and 5 males. Since that time they have continuously kept capybaras in confinement. Through selection and management, they have improved the reproduction of captive animals. The current aim is to get 16 offspring per mother per year. Newborns are weaned after 5 weeks and the mother is returned to the breeding pen.6 In Colombia, similar work is in progress, and guidelines for raising capybaras on breeding farms have been published.7 In Brazil, research has been carried out to study capybara nutrition, genetics, management, reproduction, and social behavior in total confinement.8
Throughout South America, the price of beef has increased greatly within the last few years, thereby providing a new incentive for capybara husbandry. It has also forced many campesinos to eat more wildlife, which adds another incentive for producing capybara meat on farms and thereby perhaps helping to relieve pressure on the wild stocks.
When tame, the animals are amenable to handling without physical restraint. They are so tractable that in Surinam a blind man once used one as a guide animal.
Capybaras can be raised on a variety of readily available vegetation: leaves, roots, fruits, and vegetables. They thrive in coarse grasses, if given opportunity to select nutritious parts. Their large incisors allow them to bite off short grasses that many herbivores cannot use. For instance, they eat "capybara grass" (Paspalum fasciculatum) that is abundant on river edges in Venezuela and is normally too short for cattle to graze. This makes for low-cost feeding and utilization of a resource that is otherwise unused.
Capybaras are at home in hot, humid environments and are fully adapted to life on the tropical floodplains and seasonally flooded savannas. They thrive in extreme climates where cattle struggle, such as in the parts of the lower Paraguayan Chaco where summer temperatures reach 45ÝC.9 An ecological benefit to raising capybaras is that there is no need to alter habitats by introducing exotic forage plants.
They reproduce quickly. Age at first conception for females is about 1.5 years, and the time between parturitions is generally shorter than that of goats or sheep in the tropics. Young capybaras grow so fast that in 18 months they can reach a liveweight of more than 40 kg. In their natural conditions, they are more disease resistant than cattle. The annual productivity is said to exceed that of cattle in many parts of its range.
This species is already so widely eaten in South America that the meat from farmed animals should be readily acceptable.
Capybaras occasionally raid fields and can harm sugarcane, rice, bananas, sweet potatoes, cassava, corn, and other crops. In many parts of Brazil, they are considered agricultural pests and are shot.
Confining these animals in high density may create serious problems. Infectious diseases and parasite outbreaks seem to be worse than those that occur with conventional livestock. Aggression might prove a limitation to capybara husbandry: it is almost impossible to cage two adult males together or to introduce new animals to an existing group.
The animals may transmit disease to people and livestock. They can harbor foot-and-mouth disease and are known to be susceptible to brucellosis. They also carry a form of trypanosome, Trypanosoma evansi.
Compared with cattle, capybara use only a small proportion of the total plant biomass. They are largely selective feeders, and for satisfactory performance must have sufficient area to select the plants they need. If placed in a paddock of only coarse grass, most will eventually die. Like goats and gazelles, capybara probably select a diet that is at least 15 percent richer in crude protein than a typical cattle diet.'Ý
High mortality has never been observed in Venezuela, but keeping the animals alive on a farm in some areas may not be easy. In one trial, more than half (55 percent) of the capybara died of disease, and a few of septicemia (the result of wounds incurred during fights), but most apparently of trypanosomiasis. Other losses were caused by speeding vehicles (29 percent), poaching (6 percent), and predation, mainly by jaguars (12 percent)."
RESEARCH AND CONSERVATION NEEDS
It is important for researchers to undertake the following:
- Gather specimens from different regions for comparative evaluation.
- Assess experiences of zoos and farms.
- Undertake nutritional trials.
- Initiate captive breeding trials - measurements of growth rates, space requirements, feed needs.
- Characterize the animal's productivity.
- Study the capybara's basic physiology and production potentials.
- Investigate biological factors, such as reproductive physiology, and social behavior (both in the wild and under controlled conditions).
- Determine the factors influencing capybara reproduction, growth, and development.
- Determine the animal's adaptability and economic merit in various farming systems.
- Study the influence of environment on reproduction rate.
- Determine their complementarily with water buffalo or other ruminants that normally use swampy habitats.
- Determine relative causes of mortality (such as diseases specific to capybaras) and predation (especially of the young) by spectacled caiman, crested caracayes, black vultures, and others.