Guinea pigs, also known as cavies, no longer exist in the wild. Their domestication began around 5,000 B.C., and because of their popularity as pets and food, they are now globally distributed. They are indigenous to South America, with fossil records extending as far back as 9,000 B.C.. Scientists believe that guinea pigs were domesticated from a now extinct wild species that lived in northern and western South America. European colonization of South America led to their introduction as pets in Europe and ultimately, the world over. (Morales, 1994; Sandweiss and Wing, 1997; Stahl and Norton, 1987; Terril and Clemons, 1998; Vanderlip, 2003)
Guinea pigs no longer exist in their wild, native, grassland habitat. Prior to their extinction, however, they were extremely adaptable and could survive in a variety of environments. For example, they can live in a broad range of elevations, from sea level to 4,000 m. Although studies have shown that they cannot survive in extreme hot or cold, guinea pigs can tolerate a large range of temperatures, from 22˚C in the daytime to -7˚C at night. (Cassini and Galante, 1992; Morales, 1994; National Research Council, 1991; Sandweiss and Wing, 1997; Terril and Clemons, 1998)
Guinea pigs are tailless rodents that weigh between 700 g and 1100 g, with males being larger than females. They have small, compact, cynlindrically shaped bodies, ranging from 20.3 cm to 25.4 cm in length. They have small petal-shaped ears that are laterally positioned at the apex of the head. Their eyes are laterally positioned mid-way down the snout, between the ears and nose. They have small triangular-shaped mouths, which contain 20 teeth in a (1 0 3 1)/(1 0 3 1) dental arrangement. Like many other rodents, guinea pigs have continuously growing teeth, and tooth length is maintained by grinding them together during feeding. As a result of selective breeding, 20 different phenotypes exist for hair color and 13 different phenotypes exist for coat texture and length. Their wild ancestors, however, are thought to have had short brown hair which likely camouflaged them from predators. (Banks, 1989; Morales, 1994; Terril and Clemons, 1998; Vanderlip, 2003; Banks, 1989; Morales, 1994; Terril and Clemons, 1998; Vanderlip, 2003; Banks, 1989; Guinea Lynx, 2010a; Morales, 1994; Terril and Clemons, 1998; Vanderlip, 2003)
Guinea pigs no longer exist in the wild, therefore, mating systems in natural environments are unknown. In domestic populations, mating is heavily influenced by humans. Both monogamous and polygamous systems occur, depending on how animals are housed. Prior to mating, males smell a potential mate's genital area and scent mark their mates with urine. Males are very protective of their mates, particularly when multiple males are housed with a single female. (Banks, 1989; Terril and Clemons, 1998)
Male guinea pigs reach sexual maturity at 56 to 70 days old and females reach sexual maturity at about 67 days. Female estrus occurs 3 to 4 times per year and lasts approximately 16 days. Mating and fertilization usually occur at night, within 20 hours of ovulation. Guinea pigs do not exhibit seasonal mating patterns in domestic populations. Once a female becomes pregnant, gestation lasts 59 to 72 days. The average age at first pregnancy is 175 days and average litter size is 3 pups. Lactation peaks at 5 to 8 days after parturition and weaning occurs 14 to 21 days after birth. (Banks, 1989; Terril and Clemons, 1998; Vanderlip, 2003; Ballard and Cheek, 2003; Banks, 1989; Terril and Clemons, 1998; Vanderlip, 2003)
Female guinea pigs provide only limited care to their pups. When adult females reach postpartum estrus, they pay little attention to their offspring. Although decreased body weight can occur due to maternal neglect, pups can usually survive on their own without extended maternal care. Females nurse their young for a period of 14 to 21 days until weaning. In addition, mothers stimulate their pups urinary and anal glands by licking their genital regions. Little information is available concerning paternal care. (Banks, 1989; Vanderlip, 2003)
Guinea pigs can live up to 14 years in captivity, but have an average lifespan of 8 years. Reproductively active guinea pigs generally have shorter lifespans of about 3.5 years. (Ballard and Cheek, 2003; Banks, 1989)
Guinea pigs are gregarious and prefer close contact with other conspecifics. They are active during dusk and dawn (crepuscular) and when not sleeping, spend a majority of their time grooming, feeding, or investigating the local environment. Male guinea pigs establish social hierarchies in which a single alpha male dominates subordinate males. Males are known to be extremely aggressive when competing for territory or potential mates. As a result, males are often separated when females are present. (Ballard and Cheek, 2003; Banks, 1989; National Research Council, 1991; Vanderlip, 2003)
Guinea pigs have two primary defense mechanisms, "the immobility response" and "the scatter response". When individual guinea pigs encounter a perceived threat, such as an unknown sound or movement, they remain motionless until the perceived threat has passed. This is known as "the immobility response". When a group of guinea pigs encounters a perceived threat, they often scatter in an attempt to confuse and disorient potential predators, which is known as the "the scatter response". (Ballard and Cheek, 2003; Banks, 1989; National Research Council, 1991; Vanderlip, 2003)
Guinea pigs communicate through a variety of noises, including chutts, squeaks, whines, whistles, purrs, and chirps. Chutts are used during predatory pursuit events, while whines have been observed immediately after pursuit events have ended. Squeals, squeaks, and tweets are used to communicate injury or danger; whistles and chirps are used during long distance communication and to indicate the presence of food. Lastly, purrs are thought to be indicative of contentment. (Sachser, 1998; Terril and Clemons, 1998; Vanderlip, 2003)
Guinea pigs are gregarious and often "huddle" to form tight groups for warmth and possibly security. Studies show that guinea pigs prefer low population densities. During periods of large population growth, they often create subpopulations in order to decrease local densities. (Sachser, 1998; Terril and Clemons, 1998; Vanderlip, 2003)
Guinea pigs are strict herbivores and depend on humans for food. Domestic guinea pigs are often fed lettuce, cabbage, and various types of grasses and fruit. In some cases, barley and "Timothy hay", a wide-spread perennial grass, are grown especially for consumption by domesticated mammalian herbivores such as guinea pigs. In more developed areas, they are often fed manufactured feed pellets. Feed pellets contain compressed plant material (barley or alfalfa) and many of the vitamins and minerals (e.g., vitamin C) guinea pigs require to stay healthy. (Hubbards Feed Inc., 2007; National Research Council, 1991)
Due to their domestication, guinea pigs are not subject to natural predation. Their wild relatives, such as brazilian guinea pigs (Cavea aperea), are preyed upon by small ferrets, domestic dogs (Canis lupus familiaris), domestic cats (Felis catus), coyotes (Canis latrans), wolves (Canis lupus), owls and some species of hawks. (Cassini, 1991; Morales, 1994)
Guinea pigs are host to many different parasite species, including mites, ticks, sucking lice, chewing lice, nematodes, and flukes. The most common among these are mites and lice, of which only 3 species are capable of breeding and reproducing on domesticated guinea pigs (Trixacarus caviae, Gliricola porcelli, and Chirodiscoides caviae). The most prevalent of these are mange mites (T. caviae), which burrow under the skin. If left untreated, mange mites can kill their host. In their closest wild relatives, internal parasites (e.g., flukes and nematodes) are much more common and generally inhabit the liver and small intestine. (Dittmar, 2002; Guinea Lynx, 2010b; Morales, 1994)
Globally, guinea pigs are sold as pets and in South America, as a food. Also, they are often used as subjects in biomedical research investigating scurvy, tuberculosis, juvenile diabetes, and pregnancy complications. (Basombrio, et al., 1997; Bloom, 1994; Laurien-Kehnen and Trillmich, 2003; National Research Council, 1991; Olsson, et al., 1998)
Guinea pig hair and dander can cause severe allergic reactions in some humans. (National Research Council, 1991)
Guinea pigs are extinct in the wild and only live in captivity.
There are 13 commonly recognized types or breeds of guinea pig. These include the American, American satin, Abyssinian, Abyssinian satin, Peruvian, Peruvian satin, silkie, silkie satin, teddy, teddy satin, texel, coronet and the white crested. Different breeds are often characterized by their hair color, hair texture, the degree of sheen of the pelage, and the color patterns of the pelage. (Banks, 1989; Nash, 2010)
Jordan Hixon (author), Radford University, Karen Francl (editor), Radford University, John Berini (editor), Special Projects.
living in the southern part of the New World. In other words, Central and South America.
uses sound to communicate
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
uses smells or other chemicals to communicate
active at dawn and dusk
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
union of egg and spermatozoan
an animal that mainly eats leaves.
A substance that provides both nutrients and energy to a living thing.
an animal that mainly eats fruit
An animal that eats mainly plants or parts of plants.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
Having one mate at a time.
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
the business of buying and selling animals for people to keep in their homes as pets.
having more than one female as a mate at one time
communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
uses touch to communicate
Living on the ground.
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
breeding takes place throughout the year
young are relatively well-developed when born
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