THE BLACK GIANT SQUIRRELS

The black giant squirrel or Malayan giant squirrel (Ratufa bicolor) is a large tree squirrel in the genus Ratufa native to the Indomalayan zootope. It is found in forests from northern Bangladesh, northeast India, eastern Nepal, Bhutan, southern China, Myanmar, Laos, Thailand, Malaysia, Cambodia, Vietnam, and western Indonesia.

Description

Head and body length varies from 35 to 58 centimetres (14 to 23 in) in length, and the tail is up to 60 centimetres (24 in) long, with an overall length of up to 118 centimetres (46 in). The back, ears and bushy tail are deep brown to black with a lighter buff-colored belly.

 

 

 

Habitat

Ratufa bicolor's range includes a variety of bioregions that all share the commonality of being forested. It ranges in elevation from sea level up to at least 1,400 metres (4,600 ft), in some of the most rugged land in the world. However, in recent decades, R. bicolor's habitat has been steadily encroached upon by human settlement, timber harvesting and agriculture, which along with overhunting by human predation in parts of its range, has resulted in a total loss of up to 30% of the population in the past ten years.^[1] However, in some places this species is protected from hunting by law or tradition.^[1]
In South Asia R. bicolor dwells among tropical and subtropical coniferous and broadleaf forests.^[1]
In Southeast Asia R. bicolor lives in tropical broadleaf evergreen and semi-evergreen forests, but is rarely seen in coniferous forests.^[1]
In the tropical rainforest of the Malay Peninsula and Indonesia, R. bicolor is not as abundant as elsewhere in its range, which is probably due to competition from other arboreal species (especially primates) for food in the upper forest canopy.^[1]
Among the better places to sight the black giant squirrel is the Kaziranga National Park in the state of Assam, India.^[3]

 

 Behavior

R. bicolor is diurnal and arboreal, but sometimes climbs down from the forest canopy to feed on the ground.^[1] The black giant squirrel rarely enters plantations or settlements, preferring the wild forest.^[1]
Its diet consists of seeds, pine cones, fruits, and leaves.^[1] It is primarily solitary, and has a litter of from 1 to 2 young, which it raises in a drey (or nest), often located within a hollow space of a tree.^[1]

 

 

 Taxonomy

Further study is required to determine whether Ratufa bicolor actually represents several similar species.^[1]
The table below lists the ten recognized subspecies of Ratufa bicolor, along with any synonyms associated with each subspecies:^[2]

 

THE COMMON BLACKBIRD

The common blackbird (Turdus merula) is a species of true thrush. It is also called Eurasian blackbird (especially in North America, to distinguish it from the unrelated New World blackbirds),^[2] or simply blackbird where this does not lead to confusion with a similar-looking local species. It breeds in Europe, Asia, and North Africa, and has been introduced to Canada, United States, Mexico, Peru, Brazil, Argentina, Uruguay, the Falkland Islands, Chile, South Africa, Australia and New Zealand.^[3] It has a number of subspecies across its large range; a few of the Asian subspecies are sometimes considered to be full species. Depending on latitude, the common blackbird may be resident, partially migratory, or fully migratory.
The male of the nominate subspecies, which is found throughout most of Europe, is all black except for a yellow eye-ring and bill and has a rich, melodious song; the adult female and juvenile have mainly dark brown plumage. This species breeds in woods and gardens, building a neat, mud-lined, cup-shaped nest. It is omnivorous, eating a wide range of insects, earthworms, berries, and fruits.
Both sexes are territorial on the breeding grounds, with distinctive threat displays, but are more gregarious during migration and in wintering areas. Pairs stay in their territory throughout the year where the climate is sufficiently temperate. This common and conspicuous species has given rise to a number of literary and cultural references, frequently related to its song.



 
  

Taxonomy and systematics

The common blackbird was described by Linnaeus in the 10th edition of his Systema Naturae in 1758 as Turdus merula (characterised as T. ater, rostro palpebrisque fulvis).^[4] The binomial name derives from two Latin words, turdus, "thrush", and merula, "blackbird", the latter giving rise to its French name, merle,^[5] and its Scots name, merl.^[6] About 65 species of medium to large thrushes are in the genus Turdus, characterised by rounded heads, longish, pointed wings, and usually melodious songs. The common blackbird seems to be closest in evolutionary terms to the island thrush (T. poliocephalus) of Southeast Asia and islands in the southwest Pacific, which probably diverged from T. merula stock fairly recently.^[7]
It may not immediately be clear why the name "blackbird", first recorded in 1486, was applied to this species, but not to one of the various other common black English birds, such as the carrion crow, raven, rook, or jackdaw. However, in Old English, and in modern English up to about the 18th century, "bird" was used only for smaller or young birds, and larger ones such as crows were called "fowl". At that time, the blackbird was therefore the only widespread and conspicuous "black bird" in the British Isles.^[8] Until about the 17th century, another name for the species was ouzel, ousel or wosel (from Old English osle, cf. German Amsel). Another variant occurs in Act 3 of Shakespeare's A Midsummer Night's Dream, where Bottom refers to "The Woosell cocke, so blacke of hew, With Orenge-tawny bill". The ouzel usage survived later in poetry, and still occurs as the name of the closely related ring ouzel (Turdus torquatus), and in water ouzel, an alternative name for the unrelated but superficially similar white-throated dipper (Cinclus cinclus).^[9]

Juvenile T. m. merula in England

A leucistic adult male in England with much white in the plumage

T. m. cabrerae on Gran Canaria, Canary Islands, Spain

Two related Asian Turdus thrushes, the white-collared blackbird (T. albocinctus) and the grey-winged blackbird (T. boulboul), are also named blackbirds,^[7] and the Somali thrush (T. (olivaceus) ludoviciae) is alternatively known as the Somali blackbird.^[10]
The icterid family of the New World is sometimes called the blackbird family because of some species' superficial resemblance to the common blackbird and other Old World thrushes, but they are not evolutionarily close, being related to the New World warblers and tanagers.^[11] The term is often limited to smaller species with mostly or entirely black plumage, at least in the breeding male, notably the cowbirds,^[12] the grackles,^[13] and for around 20 species with "blackbird" in the name, such as the red-winged blackbird and the melodious blackbird.^[11]

Subspecies

As would be expected for a widespread passerine bird species, several geographical subspecies are recognised. The treatment of subspecies in this article follows Clement et al. (2000).^[7]

Near adult of nominate subspecies still showing some brown in the wings

Female of subspecies merula

• T. m. merula, the nominate subspecies, breeds commonly throughout much of Europe from Iceland, the Faroes and the British Isles east to the Ural Mountains and north to about 70 N, where it is fairly scarce. A small population breeds in the Nile Valley. Birds from the north of the range winter throughout Europe and around the Mediterranean including Cyprus and North Africa. The introduced birds in Australia and New Zealand are of the nominate race.^[7]
• T. m. azorensis is a small race which breeds in the Azores. The male is darker and glossier than merula.^[14]
• T. m. cabrerae, named for Ángel Cabrera, Spanish zoologist, resembles azorensis and breeds in Madeira and the western Canary Islands.^[14]
• T. m. mauretanicus, another small dark species with a glossy black male plumage, breeds in central and northern Morocco, coastal Algeria and northern Tunisia.^[14]

First-summer male, probably subspecies aterrimus

• T m. aterrimus breeds in Hungary, south and east to southern Greece, Crete northern Turkey and northern Iran. It winters in southern Turkey, northern Egypt, Iraq and southern Iran. It is smaller than merula with a duller male and paler female plumage.^[14]
• T. m. syriacus breeds on the Mediterranean coast of southern Turkey south to Jordan, Israel and the northern Sinai. It is mostly resident, but part of the population moves south west or west to winter in the Jordan Valley and in the Nile Delta of northern Egypt south to about Cairo. Both sexes of this subspecies are darker and greyer than the equivalent merula plumages.^[7]
• T. m. intermedius is an Asiatic race breeding from Central Russia to Tajikistan, western and north east Afghanistan, and eastern China. Many birds are resident but some are altitudinal migrants and occur in southern Afghanistan and southern Iraq in winter.^[7] This is a large subspecies, with a sooty-black male and a blackish-brown female.^[15]

The Asian subspecies, the relatively large intermedius also differs in structure and voice, and may represent a distinct species.^[15] Alternatively, it has been suggested that they should be considered subspecies of T. maximus,^[7] but they differ in structure, voice and the appearance of the eye-ring.^[15][16]

Similar species

In Europe, the common blackbird can be confused with the paler-winged first-winter ring ouzel (Turdus torquatus) or the superficially similar European starling (Sturnus vulgaris).^[17] A number of similar Turdus thrushes exist far outside the range of the common blackbird, for example the South American Chiguanco thrush (Turdus chiguanco).^[18] The Indian blackbird, the Tibetan blackbird, and the Chinese blackbird were formerly considered subspecies.^[19]

Description

The common blackbird of the nominate subspecies T. m. merula is 23.5 to 29 centimetres (9.25 to 11.4 in) in length, has a long tail, and weighs 80–125 grams (2.8 to 4.4 oz). The adult male has glossy black plumage, blackish-brown legs, a yellow eye-ring and an orange-yellow bill. The bill darkens somewhat in winter.^[17] The adult female is sooty-brown with a dull yellowish-brownish bill, a brownish-white throat and some weak mottling on the breast. The juvenile is similar to the female, but has pale spots on the upperparts, and the very young juvenile also has a speckled breast. Young birds vary in the shade of brown, with darker birds presumably males.^[17] The first year male resembles the adult male, but has a dark bill and weaker eye ring, and its folded wing is brown, rather than black like the body plumage.^[7]

Distribution and habitat

The common blackbird breeds in temperate Eurasia, North Africa, the Canary Islands, and South Asia. It has been introduced to Australia and New Zealand.^[7] Populations are sedentary in the south and west of the range, although northern birds migrate south as far as northern Africa and tropical Asia in winter.^[7] Urban males are more likely to overwinter in cooler climes than rural males, an adaptation made feasible by the warmer microclimate and relatively abundant food that allow the birds to establish territories and start reproducing earlier in the year.^[20]
Common over most of its range in woodland, the common blackbird has a preference for deciduous trees with dense undergrowth. However, gardens provide the best breeding habitat with up to 7.3 pairs per hectare (nearly three pairs per acre), with woodland typically holding about a tenth of that density, and open and very built-up habitats even less.^[21] They are often replaced by the related ring ouzel in areas of higher altitude.^[22]
The common blackbird occurs up to 1000 metres (3300 ft) in Europe, 2300 metres (7590 ft) in North Africa, and at 900–1820 metres (3000–6000 ft) in peninsular India and Sri Lanka, but the large Himalayan subspecies range much higher, with T. m. maximus breeding at 3200–4800 metres (10560–16000 ft) and remaining above 2100 metres (6930 ft) even in winter.^[7]
This widespread species has occurred as a vagrant in many locations in Eurasia outside its normal range, but records from North America are normally considered to involve escapees, including, for example, the 1971 bird in Quebec.^[23] However, a 1994 record from Bonavista, Newfoundland, has been accepted as a genuine wild bird,^[7] and the species is therefore on the North American list.^[24]

Behaviour and ecology

Eggs in a nest

Two chicks in their first hours as another egg begins to hatch

Two chicks in a nest

The male common blackbird defends its breeding territory, chasing away other males or utilising a "bow and run" threat display. This consists of a short run, the head first being raised and then bowed with the tail dipped simultaneously. If a fight between male blackbirds does occur, it is usually short and the intruder is soon chased away. The female blackbird is also aggressive in the spring when it competes with other females for a good nesting territory, and although fights are less frequent, they tend to be more violent.^[21]
The bill's appearance is important in the interactions of the common blackbird. The territory-holding male responds more aggressively towards models with orange bills than to those with yellow bills, and reacts least to the brown bill colour typical of the first-year male. The female is, however, relatively indifferent to bill colour, but responds instead to shinier bills.^[25]
As long as winter food is available, both the male and female will remain in the territory throughout the year, although occupying different areas. Migrants are more gregarious, travelling in small flocks and feeding in loose groups in the wintering grounds. The flight of migrating birds comprises bursts of rapid wing beats interspersed with level or diving movement, and differs from both the normal fast agile flight of this species and the more dipping action of larger thrushes.^[14]

Breeding

Eggs, Collection Museum Wiesbaden

The male common blackbird attracts the female with a courtship display which consists of oblique runs combined with head-bowing movements, an open beak, and a "strangled" low song. The female remains motionless until she raises her head and tail to permit copulation.^[21] This species is monogamous, and the established pair will usually stay together as long as they both survive.^[14] Pair separation rates of up to 20% have been noted following poor breeding.^[26] Although the species is socially monogamous, there have been studies showing as much as 17% extra-pair paternity.^[27]
Nominate T. merula may commence breeding in March, but eastern and Indian races are a month or more later, and the introduced New Zealand birds start nesting in August.^[7][22] The breeding pair prospect for a suitable nest site in a creeper or bush, favouring evergreen or thorny species such as ivy, holly, hawthorn, honeysuckle or pyracantha.^[28] Sometimes the birds will nest in sheds or outbuildings where a ledge or cavity is used. The cup-shaped nest is made with grasses, leaves and other vegetation, bound together with mud. It is built by the female alone. She lays three to five (usually four) bluish-green eggs marked with reddish-brown blotches,^[21] heaviest at the larger end;^[22] the eggs of nominate T. merula are 2.9×2.1 centimetres (1.14×0.93 in) in size and weigh 7.2 grammes (0.25 oz), of which 6% is shell.^[29] Eggs of birds of the southern Indian races are paler than those from the northern subcontinent and Europe.^[7] The female incubates for 12–14 days before the altricial chicks are hatched naked and blind. Fledging takes another 10–19 (average 13.6) days, with both parents feeding the young and removing faecal sacs.^[14] The nest is often ill-concealed compared with those of other species, and many breeding attempts fail due to predation.^[30] The young are fed by the parents for up to three weeks after leaving the nest, and will follow the adults begging for food. If the female starts another nest, the male alone will feed the fledged young.^[21] Second broods are common, with the female reusing the same nest if the brood was successful, and three broods may be raised in the south of the common blackbird's range.^[7]
A common blackbird has an average life expectancy of 2.4 years,^[31] and, based on data from bird ringing, the oldest recorded age is 21 years and 10 months.^[32]

Songs and calls

A male singing

Song 1

Song 2

Alarm calls

The first-year male common blackbird of the nominate race may start singing as early as late January in fine weather in order to establish a territory, followed in late March by the adult male. The male's song is a varied and melodious low-pitched fluted warble, given from trees, rooftops or other elevated perches mainly in the period from March to June, sometimes into the beginning of July. It has a number of other calls, including an aggressive seee, a pook-pook-pook alarm for terrestrial predators like cats, and various chink and chook, chook vocalisations. The territorial male invariably gives chink-chink calls in the evening in an (usually unsuccessful) attempt to deter other blackbirds from roosting in its territory overnight.^[21] During winter, blackbirds can be heard quietly singing to themselves, so much so that September and October are the only months which the song cannot be heard.^[33] Like other passerine birds, it has a thin high seee alarm call for threats from birds of prey since the sound is rapidly attenuated in vegetation, making the source difficult to locate.^[34]
At least two subspecies, T. m. merula and T. m. nigropileus, will mimic other species of birds, cats, humans or alarms, but this is usually quiet and hard to detect.

Feeding

Adult male feeding on berries in Lausanne, Switzerland

The common blackbird is omnivorous, eating a wide range of insects, earthworms, seeds and berries. It feeds mainly on the ground, running and hopping with a start-stop-start progress. It pulls earthworms from the soil, usually finding them by sight, but sometimes by hearing, and roots through leaf litter for other invertebrates. Small amphibians and lizards are occasionally hunted. This species will also perch in bushes to take berries and collect caterpillars and other active insects.^[21] Animal prey predominates, and is particularly important during the breeding season, with windfall apples and berries taken more in the autumn and winter. The nature of the fruit taken depends on what is locally available, and frequently includes exotics in gardens.

Natural threats

A male attempting to distract a male kestrel close to its nest

Near human habitation the main predator of the common blackbird is the domestic cat, with newly fledged young especially vulnerable. Foxes and predatory birds, such as the sparrowhawk and other accipiters, also take this species when the opportunity arises.^[35][36] However, there is little direct evidence to show that either predation of the adult blackbirds or loss of the eggs and chicks to corvids, such as the European magpie or Eurasian jay, have an impact on population numbers.^[28]
This species is occasionally a host of parasitic cuckoos, such as the common cuckoo (Cuculus canorus), but this is minimal because the common blackbird recognizes the adult of the parasitic species and its non-mimetic eggs.^[37] In the UK, only three nests of 59,770 examined (0.005%) contained cuckoo eggs.^[38] The introduced merula blackbird in New Zealand, where the cuckoo does not occur, has, over the past 130 years, lost the ability to recognize the adult common cuckoo but still rejects non-mimetic eggs.^[39]
As with other passerine birds, parasites are common. 88% of common blackbirds were found to have intestinal parasites, most frequently Isospora and Capillaria species.^[40] and more than 80% had haematozoan parasites (Leucocytozoon, Plasmodium, Haemoproteus and Trypanosoma species).^[41]
Common blackbirds spend much of their time looking for food on the ground where they can become infested with ticks, which are external parasites that most commonly attach to the head of a blackbird.^[42] In France, 74% of rural blackbirds were found to be infested with Ixodes ticks, whereas, only 2% of blackbirds living in urban habitats were infested.^[42] This is partly because it is more difficult for ticks to find another host on lawns and gardens in urban areas than in uncultivated rural areas, and partly because ticks are likely to be commoner in rural areas, where a variety of tick hosts, such as foxes, deer and boar, are more numerous.^[42] Although ixodid ticks can transmit pathogenic viruses and bacteria, and are known to transmit Borrelia bacteria to birds,^[43] there is no evidence that this affects the fitness of blackbirds except when they are exhausted and run down after migration.^[42]
The common blackbird is one of a number of species which has unihemispheric slow-wave sleep. One hemisphere of the brain is effectively asleep, while a low-voltage EEG, characteristic of wakefulness, is present in the other. The benefit of this is that the bird can rest in areas of high predation or during long migratory flights, but still retain a degree of alertness.^[44]

Historic image of blackbird
in Nederlandsche Vogelen
(1770)

Status and conservation

The common blackbird has an extensive range, estimated at 10 million square kilometres (3.8 million square miles), and a large population, including an estimated 79 to 160 million individuals in Europe alone. The species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e., declining more than 30% in ten years or three generations), and is therefore evaluated as Least Concern.^[1] In the western Palaearctic, populations are generally stable or increasing,^[14] but there have been local declines, especially on farmland, which may be due to agricultural policies that encouraged farmers to remove hedgerows (which provide nesting places), and to drain damp grassland and increase the use of pesticides, both of which could have reduced the availability of invertebrate food.^[35]
The common blackbird was introduced to Australia by a bird dealer visiting Melbourne in early 1857,^[45] and its range has expanded from its initial foothold in Melbourne and Adelaide to include all of south-eastern Australia, including Tasmania and the Bass Strait islands.^[46] The introduced population in Australia is considered a pest because it damages a variety of soft fruits in orchards, parks and gardens including berries, cherries, stone fruit and grapes.^[45] It is thought to spread weeds, such as blackberry, and may compete with native birds for food and nesting sites.^[45][47]
The introduced common blackbird is, together with the native silvereye (Zosterops lateralis), the most widely distributed avian seed disperser in New Zealand. Introduced there along with the song thrush (Turdus philomelos) in 1862, it has spread throughout the country up to an elevation of 1,500 metres (4,921 ft), as well as outlying islands such as the Campbell and Kermadecs.^[48] It eats a wide range of native and exotic fruit, and makes a major contribution to the development of communities of naturalised woody weeds. These communities provide fruit more suited to non-endemic native birds and naturalised birds, than to endemic birds.^[49]

In culture

Sing a Song for Sixpence cover illustration

The common blackbird was seen as a sacred though destructive bird in Classical Greek folklore, and was said to die if it consumed pomegranate.^[50] Like many other small birds, it has in the past been trapped in rural areas at its night roosts as an easily available addition to the diet,^[51] and in medieval times the conceit of placing live birds under a pie crust just before serving may have been the origin of the familiar nursery rhyme:^[51]

Sing a song of sixpence,
A pocket full of rye;
Four and twenty blackbirds baked in a pie!
When the pie was opened the birds began to sing,
Oh wasn't that a dainty dish to set before the king?^[52]

The common blackbird's melodious, distinctive song is mentioned in the poem Adlestrop by Edward Thomas;

And for that minute a blackbird sang
Close by, and round him, mistier,
Farther and farther, all the birds
Of Oxfordshire and Gloucestershire.^[53]

In the English Christmas carol The Twelve Days of Christmas, the line commonly sung today as "four calling birds" is believed to have originally been written in the 18th century as "four colly birds", an archaism meaning "black as coal" that was a popular English nickname for the common blackbird.^[54]
The common blackbird, unlike many black creatures, is not normally seen as a symbol of bad luck,^[51] but R. S. Thomas wrote that there is "a suggestion of dark Places about it",^[55] and it symbolised resignation in the 17th century tragic play The Duchess of Malfi;^[56] an alternate connotation is vigilance, the bird's clear cry warning of danger.^[56]
The common blackbird is the national bird of Sweden,^[57] which has a breeding population of 1–2 million pairs,^[14] and was featured on a 30 öre Christmas postage stamp in 1970;^[58] it has also featured on a number of other stamps issued by European and Asian countries, including a 1966 4d British stamp and an 1998 Irish 30p stamp.^[59] This bird—arguably—also gives rise to the Serbian name for Kosovo, which is the possessive adjectival form of Serbian kos ("blackbird") as in Kosovo Polje ("Blackbird Field").

THE BLACK SQUIRRELS

The black squirrel occurs as a melanistic subgroup of the eastern gray squirrel and of the fox squirrel.^[1] They are common in the Midwestern United States, eastern Canada, and parts of the Northeastern United States and the United Kingdom.

Habitat

As a melanistic variety of the eastern gray and of the fox squirrel, individual black squirrels can exist wherever grey or fox squirrels live. Among eastern squirrels, grey mating pairs cannot produce black offspring. Gray squirrels have two copies of a normal pigment gene and black squirrels have either one or two copies of a mutant pigment gene. If a black squirrel has two copies of the mutant gene it will be jet black. If it has one copy of a mutant gene and one normal gene it will be brown-black.^[2] In areas with high concentrations of black squirrels, mixed litters are common.^[3] The black subgroup seems to have been predominant throughout North America prior to the arrival of Europeans in the 16th century, as its dark color helped them hide in old growth forests which tended to be very dense and shaded. As time passed, hunting and deforestation led to biological advantages for grey coloured individuals.^[4] Today, the black subgroup is particularly abundant in the northern part of the eastern gray squirrel's range.^[5][6] This is likely due to the significantly increased cold tolerance of black squirrels which lose less heat than greys.^[6] Black squirrels also enjoy concealment advantages in denser northern forests.^[3]

Distribution

Large natural populations of black (eastern gray) squirrels can be found throughout Ontario and in several parts of Ohio, Maryland, Michigan, Houston, TX, Indiana, Virginia, Washington, D.C., Iowa, Wisconsin, Minnesota, and Pennsylvania.^[7] Populations of grey squirrels in which the black subgroup is predominant can be found in these six areas as well as in smaller enclaves in Missouri, New Jersey, Delaware, southern New York, Illinois and Connecticut.^[8] Outside areas of North America where black squirrels occur naturally in abundance, there are several notable introduced populations of black squirrels:

Black squirrel near Michigan State University in Lansing, Michigan

In the United States, the city of Kent, Ohio developed a significant black squirrel population after ten were legally imported from Canada in February 1961 by Larry Woodell, the head groundskeeper at Kent State University. They have driven out native squirrels in many areas, though they peacefully coexist with most other rodent wildlife.^[9]
Black squirrels are well established in the Quad Cities area along the Iowa-Illinois boundary. According to one story, recounted in the book "The Palmers", they were first introduced on the Rock Island Arsenal Island. Some of them then escaped by jumping across ice floes on the Mississippi River when it was frozen and populated other areas in Rock Island.^[10] In Iowa, they can be found in Council Bluffs, where black fox squirrels are the town mascot, ^[11] and Iowa City. From there melanistic fox squirrels occur in increasing abundance in eastern Nebraska, including in Omaha, Lincoln, and the surrounding areas, where eastern gray squirrels are not found.^{[12] [13] [14]}
Black squirrels are abundant in Battle Creek, Michigan, and, according to legend, were first introduced there by Will Keith Kellogg, founder of the Kellogg Company, in an effort to destroy the local population of red squirrels. The story continues that this same population of squirrels was further introduced to the campus of Michigan State University by John Harvey Kellogg for the same purpose.^[15] This story was corrected by Wilbur C. "Joe" Johnson, the late chief wildlife biologist at MSU's Kellogg Biological Station near Battle Creek which includes W.K. Kellogg's former 32-acre estate at Gull Lake. Johnson, who worked at KBS for 48 years, credited Dr. John Harvey Kellogg for introducing the black squirrel to the Kellogg estate during the 1930s. Johnson said he himself trapped 20 black squirrels at Gull Lake during the early 1960s at the specific request of former MSU president John A. Hannah and released them on the East Lansing campus.^[16]
The black squirrel has become the predominant squirrel species In Van Wert, Ohio—descendants of several examples reputedly trapped in Michigan during the 1970s by two local residents who wanted to prove their existence to disbelieving friends.^{[citation needed]}
Fort Mitchell, Kentucky maintains a significant population of black squirrels after several were introduced from Detroit prior to 1977.^[4]
Black squirrels were introduced to Stanley Park in Westfield, Massachusetts, in 1948, having been brought from Michigan as a gift to a local business man. The squirrels are thriving in the park as of 2015. They have also been recently (2016) spotted in Washington State on the northern Olympic Peninsula. ^[17]
Marysville, Kansas has a notable population of black squirrels which legend claims arrived there by escaping from a travelling circus.^[18][19] The city of Hobbs, New Mexico attempted to introduce black squirrels from Marysville in 1973. However, the new population of black squirrels did not survive, likely having been killed by local fox squirrels shortly after their introduction.^[18]
Eighteen Canadian black squirrels were released at the National Zoo in Washington, D.C., near the beginning of the 20th century during President Theodore Roosevelt's administration.^[20] Since their introduction, the population of black squirrels in and near Washington has slowly but steadily increased, and black squirrels now account for up to half of the squirrel population in certain locations, such as the grounds of the Washington National Cathedral.^[20]
Eastern black squirrels were introduced at Stanford University and can be found on adjoining property in Palo Alto and Menlo Park^{[citation needed]}.
Vancouver has a growing population of black squirrels after they were introduced to the Stanley Park Peninsula before 1914. The squirrels have thrived and spread throughout the Vancouver area.^[21]
Black squirrels can also be found in the United Kingdom, where grey squirrels were first introduced from North America at the end of the 19th century.^[22] The origin of the UK's black individuals has been a topic of dispute, with initial research indicating that melanistic individuals are descendants of black zoo escapees.^[23] Regardless of their origins, the melanistic population in the UK continues to grow, and around the towns of Letchworth, Stevenage and Hitchin, as well as nearby villages such as Shillington and Meppershall in England, black squirrels are now as abundant as grey individuals.^[24] Black squirrels have been present and studied in Cambridgeshire since the 1990s; in the village of Girton three quarters of the squirrel population is black.^[25]
There is a large population of black squirrels in the Stuyvesant Town–Peter Cooper Village development in Manhattan, New York City. Residents of the large residential development have taken to nicknaming the black squirrel a "sqrat".^{[citation needed]}

Mascot and symbol

Black squirrel eating in the Society Hill neighborhood of Philadelphia, PA.

Though black squirrels are common or predominant in many areas of North America, their overall rarity (perhaps as few as 1 in 10,000)^[4] has caused many towns, cities, colleges, and universities to take special pride in their populations of black squirrels. Several cities and towns in the United States and one in Canada make efforts to publicly promote their local populations of black squirrels.

 


 Several colleges and universities in the United States promote the black squirrel as an official or unofficial mascot:

• Haverford College where the black squirrel is the official mascot of varsity athletics^[30]
• Kent State University^[9] which each year holds a Black Squirrel Festival (located in the Risman Plaza during the second week of September) to honour the university's growing black squirrel population.^[28] It features live music, vendors and an overall tribute to the black squirrels seen throughout the campus. Beyond the festival, other businesses and organizations in Kent are named for the black squirrel, including Black Squirrel Brewing Company, Black Squirrel Radio^[31] and Black Squirrel Books, an imprint of the Kent State University Press.^[32]
• Albion College where the black squirrel has become a significant symbol on campus^[33]
• Sarah Lawrence College where the campus coffee shop is named for the black squirrel.^[34] The black squirrel is also used as an unofficial mascot, with the bookstore selling plush squirrels.

 

THE GUINEA PIGS

The guinea pig (Cavia porcellus), also called the cavy or domestic guinea pig, is a species of rodent belonging to the family Caviidae and the genus Cavia. Despite their common name, these animals are not in the pig family, nor are they from Guinea. They originated in the Andes, and earlier studies based on biochemistry and hybridization suggested they are domesticated descendants of a closely related species of cavy such as Cavia aperea, C. fulgida, or C. tschudii and, therefore, do not exist naturally in the wild.^[1][2] Recent studies applying molecular markers,^[3][4] in addition to studying the skull and skeletal morphology of current and mummified animals,^[5] revealed that the ancestor is most likely Cavia tschudii.
The domestic guinea pig plays an important role in the folk culture of many Indigenous South American groups, especially as a food source, but also in folk medicine and in community religious ceremonies.^[6] Since the 1960s, efforts have been made to increase consumption of the animal outside South America.^[7]
In Western societies, the domestic guinea pig has enjoyed widespread popularity as a household pet since its introduction by European traders in the 16th century. Their docile nature and responsiveness to handling and feeding, and the relative ease of caring for them, continue to make guinea pigs a popular pet. Organizations devoted to competitive breeding of guinea pigs have been formed worldwide, and many specialized breeds of guinea pig, with varying coat colors and compositions, are cultivated by breeders.
Biological experimentation on guinea pigs has been carried out since the 17th century. The animals were frequently used as model organisms in the 19th and 20th centuries, resulting in the epithet "guinea pig" for a test subject, but have since been largely replaced by other rodents such as mice and rats. They are still used in research, primarily as models for human medical conditions such as juvenile diabetes, tuberculosis, scurvy, and pregnancy complications.

History

The guinea pig was first domesticated as early as 5000 BC for food by tribes in the Andean region of South America (the present-day southern part of Colombia, Ecuador, Peru, and Bolivia),^[8] some thousands of years after the domestication of the South American camelids.^[9] Statues dating from circa 500 BC to 500 AD that depict guinea pigs have been unearthed in archaeological digs in Peru and Ecuador.^[10] The Moche people of ancient Peru worshipped animals and often depicted the guinea pig in their art.^[11] From about 1200 AD to the Spanish conquest in 1532, selective breeding resulted in many varieties of domestic guinea pigs, which form the basis for some of the modern domestic breeds.^[12] They continue to be a food source in the region; many households in the Andean highlands raise the animal, which subsists on the family's vegetable scraps.^[13] Folklore traditions involving guinea pigs are numerous; they are exchanged as gifts, used in customary social and religious ceremonies, and frequently referenced in spoken metaphors.^[14] They also play a role in traditional healing rituals by folk doctors, or curanderos, who use the animals to diagnose diseases such as jaundice, rheumatism, arthritis, and typhus.^[15] They are rubbed against the bodies of the sick, and are seen as a supernatural medium.^[16] Black guinea pigs are considered especially useful for diagnoses.^[17] The animal also may be cut open and its entrails examined to determine whether the cure was effective.^[18] These methods are widely accepted in many parts of the Andes, where Western medicine is either unavailable or distrusted.^[19]
Spanish, Dutch, and English traders brought guinea pigs to Europe, where they quickly became popular as exotic pets among the upper classes and royalty, including Queen Elizabeth I.^[8] The earliest known written account of the guinea pig dates from 1547, in a description of the animal from Santo Domingo; because cavies are not native to Hispaniola, the animal was earlier believed to have been introduced there by Spanish travelers.^[1] However, based on more recent excavations on West Indian islands, the animal must have been introduced by ceramic-making horticulturalists from South America to the Caribbean around 500 BC,^[20] and it was present in the Ostionoid period, for example, on Puerto Rico,^[21] long before the advent of the Spaniards. The guinea pig was first described in the West in 1554 by the Swiss naturalist Conrad Gessner.^[22] Its binomial scientific name was first used by Erxleben in 1777; it is an amalgam of Pallas' generic designation (1766) and Linnaeus' specific conferral (1758).^[1] The earliest known illustration of a domestic guinea pig is a painting (artist unknown) in the collection of the National Portrait Gallery in London, dated to 1580, which shows a girl in typical Elizabethan dress holding a tortoise-shell guinea pig in her hands; she is flanked by her two brothers, one of whom holds a pet bird.^[23] The picture dates from the same period as the oldest recorded guinea pig remains in England, which are a partial cavy skeleton found at Hill Hall (Essex), an Elizabethan manor house, and dated to around 1575.^[23]

Name

The scientific name of the common species is Cavia porcellus, with porcellus being Latin for "little pig". Cavia is New Latin; it is derived from cabiai, the animal's name in the language of the Galibi tribes once native to French Guiana.^[24] Cabiai may be an adaptation of the Portuguese çavia (now savia), which is itself derived from the Tupi word saujá, meaning rat.^[25] Guinea pigs are called quwi or jaca in Quechua and cuy or cuyo (plural cuyes, cuyos) in the Spanish of Ecuador, Peru, and Bolivia.^[26] Ironically, breeders tend to use the more formal "cavy" to describe the animal, while in scientific and laboratory contexts, it is far more commonly referred to by the more colloquial "guinea pig".^[27]
How the animals came to be called "pigs" is not clear. They are built somewhat like pigs, with large heads relative to their bodies, stout necks, and rounded rumps with no tail of any consequence; some of the sounds they emit are very similar to those made by pigs, and they also spend a large amount of time eating.^[27][28] They can survive for long periods in small quarters, like a 'pig pen', and were thus easily transported on ships to Europe.^[27]
The animal's name alludes to pigs in many European languages. The German word for them is Meerschweinchen, literally "little sea pig", which has been translated into Polish as świnka morska, into Hungarian as tengerimalac, and into Russian as морская свинка. This derives from the Middle High German name merswin. This originally meant "dolphin" and was used because of the animals' grunting sounds (which were thought to be similar).^[29] Many other, possibly less scientifically based explanations of the German name exist. For example, sailing ships stopping to reprovision in the New World would pick up stores of guinea pigs, which provided an easily transportable source of fresh meat. The French term is cochon d'Inde (Indian pig) or cobaye; the Dutch call it Guinees biggetje (Guinean piglet) or cavia (while in some Dutch dialects it is called Spaanse rat); and in Portuguese, the guinea pig is variously referred to as cobaia, from the Tupi word via its Latinization, or as porquinho da Índia (little Indian pig). This is not universal; for example, the common word in Spanish is conejillo de Indias (little rabbit of the Indies).^[26] The Chinese refer to them as 豚鼠 (túnshǔ, 'pig mouse'), and sometimes as Netherlands pig (荷蘭豬, hélánzhū) or Indian mouse (天竺鼠, tiānzhúshǔ). The Japanese word for guinea pig is "モルモット" (morumotto), which derives from the name of another mountain-dwelling rodent, the marmot; this is what guinea pigs were called by the Dutch traders who first brought them to Nagasaki in 1843.
The origin of "guinea" in "guinea pig" is harder to explain. One proposed explanation is that the animals were brought to Europe by way of Guinea, leading people to think they had originated there.^[27] "Guinea" was also frequently used in English to refer generally to any far-off, unknown country, so the name may simply be a colorful reference to the animal's exotic appeal.^[30][31] Another hypothesis suggests the "guinea" in the name is a corruption of "Guiana", an area in South America, though the animals are not native to that region.^[30][32] A common misconception is that they were so named because they were sold for the price of a guinea coin; this hypothesis is untenable, because the guinea was first struck in England in 1663, and William Harvey used the term "Ginny-pig" as early as 1653.^[33] Others believe "guinea" may be an alteration of the word coney (rabbit); guinea pigs were referred to as "pig coneys" in Edward Topsell's 1607 treatise on quadrupeds.^[27]

Traits and environment

Main article: List of guinea pig breeds

Two parti-colored Abyssinian guinea pigs

Guinea pigs are large for rodents, weighing between 700 and 1,200 g (1.5 and 2.6 lb), and measuring between 20 and 25 cm (8 and 10 in) in length.^[34] They typically live an average of four to five years, but may live as long as eight years.^[35] According to the 2006 Guinness World Records, the longest living guinea pig survived 14 years, 10.5 months.^[36]
In the 1990s, a minority scientific opinion emerged proposing that caviomorphs, such as guinea pigs, chinchillas, and degus, are not rodents and should be reclassified as a separate order of mammals (similar to lagomorphs).^[37][38] Subsequent research using wider sampling has restored consensus among mammalian biologists that the current classification of rodents as monophyletic is justified.^[39][40]

Natural habitat

C. porcellus is not found naturally in the wild; it is likely descended from some closely related species of cavies, such as C. aperea, C. fulgida, and C. tschudii, which are still commonly found in various regions of South America.^[1] Some species of cavy identified in the 20th century, such as C. anolaimae and C. guianae, may be domestic guinea pigs that have become feral by reintroduction into the wild.^[12] Wild cavies are found on grassy plains and occupy an ecological niche similar to that of cattle. They are social, living in the wild in small groups which consist of several females (sows), a male (boar), and the young (which in a break with the preceding porcine nomenclature are called pups). They move together in groups (herds) eating grass or other vegetation, and do not store food.^[41] While they do not burrow or build nests, they frequently seek shelter in the burrows of other animals, as well as in crevices and tunnels formed by vegetation.^[41] They tend to be most active during dawn and dusk, when it is harder for predators to spot them.^[42]

Domestic habitat

Domesticated guinea pigs thrive in groups of two or more; groups of sows, or groups of one or more sows and a neutered boar are common combinations. Guinea pigs learn to recognize and bond with other individual guinea pigs, and testing of boars shows their neuroendocrine stress response is significantly lowered in the presence of a bonded female when compared to the presence of unfamiliar females.^[43] Groups of boars may also get along, provided their cage has enough space, they are introduced at an early age, and no females are present.^[44] Domestic guinea pigs have developed a different biological rhythm from their wild counterparts, and have longer periods of activity followed by short periods of sleep in between.^[42] Activity is scattered randomly over the day; aside from avoidance of intense light, no regular circadian patterns are apparent.^[42]

This cat has accepted this pair of guinea pigs. The success of this type of interspecies interaction varies according to the individual animals involved.

Domestic guinea pigs generally live in cages, although some owners of large numbers of guinea pigs dedicate entire rooms to their pets. Cages with solid or wire mesh floors are used, although wire mesh floors can cause injury and may be associated with an infection commonly known as bumblefoot (ulcerative pododermatitis).^[45] "Cubes and Coroplast" (or C&C) style cages are now a common choice.^[46] Cages are often lined with wood shavings or a similar material. Bedding made from red cedar (Eastern or Western) and pine, both softwoods, were commonly used in the past, but these materials are now believed to contain harmful phenols (aromatic hydrocarbons) and oils.^[47] Safer beddings made from hardwoods (such as aspen), paper products, and corn cob materials are other alternatives.^[47] Guinea pigs tend to be messy within their cages; they often jump into their food bowls or kick bedding and feces into them, and their urine sometimes crystallizes on cage surfaces, making it difficult to remove.^[48] After its cage has been cleaned, a guinea pig typically urinates and drags its lower body across the floor of the cage to mark its territory.^[49] Male guinea pigs may also mark their territory in this way when they are taken out of their cages.
Guinea pigs do not generally thrive when housed with other species. Housing of guinea pigs with other rodents such as gerbils and hamsters may increase instances of respiratory and other infections,^[50] and such rodents may act aggressively toward the guinea pig.^[51] Larger animals may regard guinea pigs as prey, though some (such as dogs) can be trained to accept them.^[52] Opinion is divided over the cohousing of guinea pigs and domestic rabbits. Some published sources say that guinea pigs and rabbits complement each other well when sharing a cage.^[52][53] However, as lagomorphs, rabbits have different nutritional requirements, so the two species cannot be fed the same food.^[54] Rabbits may also harbor diseases (such as respiratory infections from Bordetella and Pasteurella), to which guinea pigs are susceptible.^[55] Even the dwarf rabbit is much stronger than the guinea pig and may cause intentional or inadvertent injury.^[56]

Behavior

Guinea pigs can learn complex paths to food, and can accurately remember a learned path for months. Their strongest problem-solving strategy is motion.^[57] While guinea pigs can jump small obstacles, they are poor climbers, and are not particularly agile. They startle extremely easily, and either freeze in place for long periods or run for cover with rapid, darting motions when they sense danger.^[42] Larger groups of startled guinea pigs "stampede", running in haphazard directions as a means of confusing predators.^[58] When excited, guinea pigs may repeatedly perform little hops in the air (known as "popcorning"), a movement analogous to the ferret's war dance.^[59] They are also exceedingly good swimmers.^[60]

Guinea pigs "social groom"

Like many rodents, guinea pigs sometimes participate in social grooming, and they regularly self-groom.^[61] A milky-white substance is secreted from their eyes and rubbed into the hair during the grooming process.^[62] Groups of boars often chew each other's hair, but this is a method of establishing hierarchy within a group, rather than a social gesture.^[60] Dominance is also established through biting (especially of the ears), piloerection, aggressive noises, head thrusts, and leaping attacks.^[63] Non-sexual simulated mounting for dominance is also common among same-sex groups.
Guinea pig sight is not as good as that of a human, but they have a wider angle of vision (about 340°) and see in partial color (dichromacy). They have well-developed senses of hearing, smell, and touch.^[64][65] Vocalization is the primary means of communication between members of the species.^[66] These are the most common sounds made by the guinea pig:^[67]

• A "wheek" is a loud noise, the name of which is onomatopoeic, also known as a whistle. An expression of general excitement, it may occur in response to the presence of its owner or to feeding. It is sometimes used to find other guinea pigs if they are running. If a guinea pig is lost, it may wheek for assistance.  listen (help·info)
• A bubbling or purring sound is made when the guinea pig is enjoying itself, such as when being petted or held. It may also make this sound when grooming, crawling around to investigate a new place, or when given food.  listen (help·info)
• A rumbling sound is normally related to dominance within a group, though it can also come as a response to being scared or angry. In these cases, the rumble often sounds higher and the body vibrates shortly. While courting, a male usually purrs deeply, swaying and circling the female^[68] in a behavior called "rumblestrutting". A low rumble while walking away reluctantly shows passive resistance.  listen (help·info)
• Chutting and whining are sounds made in pursuit situations, by the pursuer and pursuee, respectively.  listen (help·info)
• A chattering sound is made by rapidly gnashing the teeth, and is generally a sign of warning. Guinea pigs tend to raise their heads when making this sound.
• Squealing or shrieking is a high-pitched sound of discontent, in response to pain or danger.  listen (help·info)
• Chirping, a less-common sound, likened to bird song, seems to be related to stress, or when a baby guinea pig wants to be fed. Very rarely, the chirping will last for several minutes.  listen (help·info)

Breeding

Pregnant sow one week before delivering three pups

The guinea pig is able to breed year-round, with birth peaks usually coming in the spring; as many as five litters can be produced per year.^[12] The gestation period lasts from 59–72 days, with an average of 63–68 days.^[49] Because of the long gestation period and the large size of the pups, pregnant females may become large and eggplant-shaped, although the change in size and shape varies. Unlike the offspring of most other rodents, which are altricial at birth, newborn pups are well-developed with hair, teeth, claws, and partial eyesight;^[60] they are immediately mobile, and begin eating solid food immediately, though they continue to suckle. Litters yield one to six pups, with an average of three;^[69] the largest recorded litter size is 17.^[70]
In smaller litters, difficulties may occur during labour due to over-sized pups. Large litters result in higher incidences of stillbirth, but because the pups are delivered at an advanced stage of development, lack of access to the mother's milk has little effect on the mortality rate of newborns.^[71] Cohabitating females assist in mothering duties if lactating.^[72]
Guinea pigs also practice alloparental care, in which a female may adopt the pup or pups of another. This might take place if the original parents die or are for some reason separated from them. This behavior is common, and is seen in many other animal species such as the elephant.^[73]
Male and female guinea pigs do not differ in external appearance apart from general size. The position of the anus is very close to the genitals in both sexes. Female genitals are distinguished by a Y-shaped configuration formed from a vulvar flap, while the male genitals may look similar, with the penis and anus forming a like shape, the penis will protrude if pressure is applied to the surrounding hair.^[74] The male's testes may also be visible externally from scrotal swelling.

Guinea pig pup at eight hours old

Males reach sexual maturity at 3–5 weeks; females can be fertile as early as four weeks and can carry litters before they are adults.^[75] Females that have never given birth may develop irreversible fusing of the pubic symphysis, a joint in the pelvis, due to calcification which may occur between six and 10 months of age.^[49]:73[76] If they become pregnant after this has happened, the birth canal will not widen sufficiently; this may lead to dystocia and death as they attempt to give birth.^[77] Calcification of the female's pubic symphysis (if not bred) is a common myth. The reason for potential calcification is a metabolic disease, like ochronosis. A healthy, normal female guinea pig's pubic symphysis does not calcify.^[78] Females can become pregnant 6–48 hours after giving birth, but it is not healthy for a female to be thus constantly pregnant.^[79]
Toxemia of pregnancy is common and kills many pregnant females. Signs of toxemia include anorexia, lack of energy, excessive salivation, a sweet or fruity breath odor due to ketones, and seizures in advanced cases.^[80] Pregnancy toxemia appears to be most common in hot climates.^[81] Other serious complications of pregnancy can include a prolapsed uterus, hypocalcaemia, and mastitis.^[82]

Diet

A silver agouti guinea pig eating grass

A short-haired guinea pig eating a piece of apple

Grass is the guinea pig's natural diet. Their molars are particularly suited for grinding plant matter, and grow continuously throughout the animal's life.^[83] Most grass-eating mammals are quite large and have a long digestive tract; while guinea pigs have much longer colons than most rodents, they must also supplement their diet by coprophagy, the eating of their own feces.^[84] However, they do not consume all their feces indiscriminately, but produce special soft pellets, called cecotropes, which recycle B vitamins, fiber, and bacteria required for proper digestion.^[85][86] The cecotropes (or caecal pellets) are eaten directly from the anus, unless the guinea pig is pregnant or obese.^[54] They share this behaviour with rabbits. In geriatric boars or sows (the condition is rarer in young ones), the muscles which allow the softer pellets to be expelled from the anus for consumption can become weak. This creates a condition known as anal impaction, which prevents the boar from redigesting cecotropes, though harder pellets may pass through the impacted mass.^[87] The condition may be temporarily alleviated by carefully expelling the impacted feces.
Guinea pigs benefit from feeding on fresh grass hay, such as timothy hay, in addition to food pellets which are often based from timothy. Alfalfa is also a popular food choice; most guinea pigs will eat large amounts of alfalfa when offered it,^[13][88] though some controversy exists over the feeding of alfalfa to adult guinea pigs. Some pet owners and veterinary organizations have advised that, as a legume rather than a grass hay, alfalfa consumed in large amounts may lead to obesity, as well as bladder stones due to excess calcium, in any but pregnant and very young guinea pigs.^[89][90] However, published scientific sources mention alfalfa as a source for replenishment of protein, amino acids, and fiber.^[91][92][93]
Like humans, but unlike most other mammals, guinea pigs cannot synthesize their own vitamin C and must obtain this vital nutrient from food. If guinea pigs do not ingest enough vitamin C, they can suffer from potentially fatal scurvy. Guinea pigs require about 10 mg of vitamin C daily (20 mg if pregnant), which can be obtained through fresh, raw fruits and vegetables (such as broccoli, apple, cabbage, carrot, celery, and spinach) or through dietary supplements.^[94] Healthy diets for guinea pigs require a complex balance of calcium, magnesium, phosphorus, potassium, and hydrogen ions; adequate amounts of vitamins E, A, and D are also necessary.^[95] Imbalanced diets have been associated with muscular dystrophy, metastatic calcification, difficulties with pregnancy, vitamin deficiencies, and teeth problems.^[96][97] Guinea pigs tend to be fickle eaters when it comes to fresh fruits and vegetables, having learned early in life what is and is not appropriate to consume, and their habits are difficult to change after maturity.^[92][98] They do not respond well to sudden changes in diet; they may stop eating and starve rather than accept new food types.^[60] A constant supply of hay or other food is generally recommended, as guinea pigs feed continuously and may develop habits such as chewing on their own hair if food is not present.^[99] Because guinea pigs' teeth grow constantly, they routinely gnaw, lest their teeth become too large for their mouths, a common problem in rodents.^[46] Guinea pigs also chew on cloth, paper, plastic, and rubber.
A number of plants are poisonous to guinea pigs, including bracken, bryony, buttercup, charlock, deadly nightshade, foxglove, hellebore, hemlock, lily of the valley, mayweed, monkshood, privet, ragwort, rhubarb, speedwell, toadflax (both Linaria vulgaris and Linaria dalmatica), and wild celery.^[100] Additionally, any plant which grows from a bulb (e.g., tulip or onion) is normally considered poisonous,^[101] as well as ivy and oak tree leaves.

Health

A parti-colored guinea pig suffering from torticollis, or wry neck

Common ailments in domestic guinea pigs include respiratory tract infections, diarrhea, scurvy (vitamin C deficiency, typically characterized by sluggishness), abscesses due to infection (often in the neck, due to hay embedded in the throat, or from external scratches), and infections by lice, mites, or fungus.^[102]
Mange mites (Trixacarus caviae) are a common cause of hair loss, and other symptoms may also include excessive scratching, unusually aggressive behavior when touched (due to pain), and, in some instances, seizures.^[103] Guinea pigs may also suffer from "running lice" (Gliricola porcelli), a small, white insect which can be seen moving through the hair; their eggs, which appear as black or white specks attached to the hair, are sometimes referred to as "static lice". Other causes of hair loss can be due to hormonal upsets caused by underlying medical conditions such as ovarian cysts.^[104]
Foreign bodies, especially small pieces of hay or straw, can become lodged in the eyes of guinea pigs, resulting in excessive blinking, tearing, and in some cases an opaque film over the eye due to corneal ulcer.^[105] Hay or straw dust can also cause sneezing. While it is normal for guinea pigs to sneeze periodically, frequent sneezing may be a symptom of pneumonia, especially in response to atmospheric changes. Pneumonia may also be accompanied by torticollis and can be fatal.^[106]
Because the guinea pig has a stout, compact body, it more easily tolerates excessive cold than excessive heat.^[107] Its normal body temperature is 101–104 °F (38–40 °C),^[108] so its ideal ambient air temperature range is similar to a human's, about 65–75 °F (18–24 °C).^[107] Consistent ambient temperatures in excess of 90 °F (32 °C) have been linked to hyperthermia and death, especially among pregnant sows.^[107] Guinea pigs are not well suited to environments that feature wind or frequent drafts,^[109] and respond poorly to extremes of humidity outside of the range of 30–70%.^[110]
Guinea pigs are prey animals whose survival instinct is to mask pain and signs of illness, and many times health problems may not be apparent until a condition is severe or in its advanced stages. Treatment of disease is made more difficult by the extreme sensitivity guinea pigs have to most antibiotics, including penicillin, which kill off the intestinal flora and quickly bring on episodes of diarrhea and in some cases, death.^[111][112]
Similar to the inherited genetic diseases of other breeds of animal (such as hip dysplasia in canines), a number of genetic abnormalities of guinea pigs have been reported. Most commonly, the roan coloration of Abyssinian guinea pigs is associated with congenital eye disorders and problems with the digestive system.^[113] Other genetic disorders include "waltzing disease" (deafness coupled with a tendency to run in circles), palsy, and tremor conditions.^[114]

Pets

See also: List of guinea pig breeds

Handling, temperament and socialization

If handled correctly early in life, guinea pigs become amenable to being picked up and carried, and seldom bite or scratch.^[60] They are timid explorers and often hesitate to attempt an escape from their cage even when an opportunity presents itself.^[53] Still, they show considerable curiosity when allowed to walk freely, especially in familiar and safe terrain. Guinea pigs that become familiar with their owner will whistle on the owner's approach; they will also learn to whistle in response to the rustling of plastic bags or the opening of refrigerator doors, where their food is most commonly stored. In Switzerland, owning a single guinea pig is considered harmful to its well-being and forbidden by law.^[115]

Appearance, coat and grooming

Black-haired Silkie Guinea pig

Domesticated guinea pigs occur in many breeds, which have been developed since their introduction to Europe and North America. These varieties vary in hair and color composition. The most common varieties found in pet stores are the English shorthair (also known as the American), which have a short, smooth coat, and the Abyssinian, whose coat is ruffled with cowlicks, or rosettes. Also popular among breeders are the Peruvian and the Sheltie (or Silkie), both straight longhair breeds, and the Texel, a curly longhair. Grooming of guinea pigs is primarily accomplished using combs or brushes. Shorthair breeds are typically brushed weekly, while longhair breeds may require daily grooming.^[116]

Clubs and associations

Cavy clubs and associations dedicated to the showing and breeding of guinea pigs have been established worldwide. The American Cavy Breeders Association, an adjunct to the American Rabbit Breeders' Association, is the governing body in the United States and Canada.^[117] The British Cavy Council governs cavy clubs in the United Kingdom. Similar organizations exist in Australia (Australian National Cavy Council)^[118] and New Zealand (New Zealand Cavy Council).^[119] Each club publishes its own standard of perfection and determines which breeds are eligible for showing.

Allergies to pet guinea pigs

Allergic symptoms, including rhinitis, conjunctivitis, and asthma, have been documented in laboratory animal workers who come into contact with guinea pigs.^[120][121] Allergic reactions following direct exposure to guinea pigs in domestic settings have also been reported.^[120] Two major guinea pig allergens, Cav p I and Cav p II, have been identified in guinea pig fluids (urine and saliva) and guinea pig dander.^[120] People who are allergic to guinea pigs are usually allergic to hamsters and gerbils, as well.^[122] Allergy shots can successfully treat an allergy to guinea pigs, although treatment can take up to 18 months.

Cultural and media influence

A lilac, orange, and white Satin Peruvian guinea pig (show-length coat)

As a result of their widespread popularity, especially in households with children, guinea pigs have shown a presence in culture and media. Some noted appearances of the animal in literature include the short story "Pigs Is Pigs" by Ellis Parker Butler, which is a tale of bureaucratic incompetence. Two guinea pigs held at a railway station breed unchecked while humans argue as to whether they are "pigs" or "pets" for the purpose of determining freight charges.^[123] Butler's story, in turn, inspired the Star Trek: The Original Series episode "The Trouble With Tribbles", written by David Gerrold.^[124] In the Golden Hamster Saga books, two guinea pigs named Enrico and Caruso are modern-day thespians (named after Enrico Caruso) who serve as secondary characters, and often irritate the main character, Freddy Auratus, that strongly dislikes their acting antics.

In children's literature

The Fairy Caravan, a novel by Beatrix Potter,^[125] and Michael Bond's Olga da Polga series for children,^[126] both feature guinea pigs as the protagonist. Another appearance is in The Magician's Nephew by C. S. Lewis: in the first (chronologically) of his The Chronicles of Narnia series, a guinea pig is the first creature to travel to the Wood between the Worlds.^[127] In Ursula Dubosarsky's Maisie and the Pinny Gig, a little girl has a recurrent dream about a giant guinea pig, while guinea pigs feature significantly in several of Dubosarsky's other books, including the young adult novel The White Guinea Pig and The Game of the Goose.^[128]

In film and television

Guinea pigs have also been featured in film and television. In the TV movie Shredderman Rules, the main character and the main character's crush both have guinea pigs which play a minor part in the plot. A guinea pig named Rodney, voiced by Chris Rock, was a prominent character in the 1998 film Dr. Dolittle, and Linny the Guinea pig is a co-star on Nick Jr.'s Wonder Pets. Guinea pigs were used in some major advertising campaigns in the 1990s and 2000s, notably for Egg Banking plc,^[129] Snapple, and Blockbuster Video.^[130] The Blockbuster campaign is considered by some guinea pig advocates to have been a factor in the rise of caging guinea pigs and rabbits together.^[56] In the South Park season 12 episode "Pandemic 2: The Startling", giant guinea pigs dressed in costumes rampage over the Earth.^[131] The 2009 Walt Disney Pictures movie G-Force features a group of highly intelligent guinea pigs trained as operatives of the U.S. government. A video game based on the movie was also released. A guinea pig named Bugsy appears in the 2008 film Bedtime Stories. A guinea pig named Cashew features prominently in the second season of the U.S. adaptation of House of Cards.

Scientific research

The use of guinea pigs in scientific experimentation dates back at least to the 17th century, when the Italian biologists Marcello Malpighi and Carlo Fracassati conducted vivisections of guinea pigs in their examinations of anatomic structures.^[132] In 1780, Antoine Lavoisier used a guinea pig in his experiments with the calorimeter, a device used to measure heat production. The heat from the guinea pig's respiration melted snow surrounding the calorimeter, showing that respiratory gas exchange is a combustion, similar to a candle burning.^[133] Guinea pigs played a major role in the establishment of germ theory in the late 19th century, through the experiments of Louis Pasteur, Émile Roux, and Robert Koch.^[134] Guinea pigs have been launched into orbital space flight several times, first by the USSR on the Sputnik 9 biosatellite of March 9, 1961 – with a successful recovery.^[135] China also launched and recovered a biosatellite in 1990 which included guinea pigs as passengers.^[136]
In English, the term 'guinea pig' is commonly used as a metaphor for a subject of scientific experimentation, or any experiment or test in modern times. This dates back to the early 20th century; the Oxford English Dictionary notes its first usage in this capacity in 1913.^[137] In 1933, Consumers Research founders F. J. Schlink and Arthur Kallet wrote a book entitled 100,000,000 Guinea Pigs, extending the metaphor to consumer society.^[138] The book became a national bestseller in the United States, thus further popularizing the term, and spurred the growth of the consumer protection movement.^[139] The negative connotation of the term was later employed in the novel The Guinea Pigs by Czech author Ludvík Vaculík as an allegory for Soviet totalitarianism.^[140] Guinea pigs were popular laboratory animals until the later 20th century; about 2.5 million guinea pigs were used annually in the U.S. for research in the 1960s,^[141] but that total decreased to about 375,000 by the mid-1990s.^[60] As of 2007, they constitute about 2% of the current total of laboratory animals.^[141] In the past, they were widely used to standardize vaccines and antiviral agents; they were also often employed in studies on the production of antibodies in response to extreme allergic reactions, or anaphylaxis.^[142] Less common uses included research in pharmacology and irradiation.^[142] Since the middle 20th century, they have been replaced in laboratory contexts primarily by mice and rats. This is in part because research into the genetics of guinea pigs has lagged behind that of other rodents, although geneticists W. E. Castle and Sewall Wright made a number of contributions to this area of study, especially regarding coat color.^[114][143] In 2004, the U.S.'s National Human Genome Research Institute announced plans to sequence the genome of the domestic guinea pig.^[144]
The guinea pig was most extensively implemented in research and diagnosis of infectious diseases.^[142] Common uses included identification of brucellosis, Chagas disease, cholera, diphtheria, foot-and-mouth disease, glanders, Q fever, Rocky Mountain spotted fever, and various strains of typhus.^[142] They are still frequently used to diagnose tuberculosis, since they are easily infected by human tuberculosis bacteria.^[141] Because guinea pigs are one of the few animals which, like humans and other primates, cannot synthesize vitamin C, but must obtain it from their diet, they are ideal for researching scurvy.^[141] From the accidental discovery in 1907 that scurvy could be induced in guinea pigs, to their use to prove the chemical structure of the "ascorbutic factor" in 1932, the guinea pig model proved a crucial part of vitamin C research.^[145][146]
Complement, an important component for serology, was first isolated from the blood of the guinea pig.^[141] Guinea pigs have an unusual insulin mutation,^[147] and are a suitable species for the generation of anti-insulin antibodies.^[148] Present at a level 10 times that found in other mammals, the insulin in guinea pigs may be important in growth regulation, a role usually played by growth hormone.^[149] Additionally, guinea pigs have been identified as model organisms for the study of juvenile diabetes and, because of the frequency of pregnancy toxemia, of pre-eclampsia in human females.^[72] Their placental structure is similar to that of humans, and their gestation period can be divided into trimesters that resemble the stages of fetal development in humans.^[150]
Guinea pig strains used in scientific research are primarily outbred strains. Aside from the common American or English stock, the two main outbred strains in laboratory use are the Hartley and Dunkin-Hartley; these English strains are albino, although pigmented strains are also available.^[151] Inbred strains are less common and are usually used for very specific research, such as immune system molecular biology. Of the inbred strains that have been created, the two still used with any frequency are, following Sewall Wright's designations, "Strain 2" and "Strain 13".^[114][151]
Hairless breeds of guinea pigs have been used in scientific research since the 1980s, particularly for dermatological studies. A hairless and immunodeficient breed was the result of a spontaneous genetic mutation in inbred laboratory strains from the Hartley stock at the Eastman Kodak Company in 1979.^[152] An immunocompetent hairless breed was also identified by the Institute Armand Frappier in 1978, and Charles River Laboratories has reproduced this breed for research since 1982.^[153] Cavy fanciers then began acquiring hairless breeds, and the pet hairless varieties are referred to as "skinny pigs".