Colored squirrels
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Red squirrel of the subspecies Sciurus variegatoides atrirufus |
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| Sciurus variegatoides | ||||||||||||
| Ogilby , 1839 |
The red squirrel ( Sciurus variegatoides ) is a Central American species of rodent from the squirrel family (Sciuridae); therein it is assigned to the genus of the squirrel . The species was scientifically described by William Ogilby in 1839 as one of the first mammalian species in Central America . The animals came from a collection of Captain Edward Belcher , which he had created on his journey along the Pacific coast of South and Central America.
The colorful squirrel is characterized by a very large number of variants with different coat colors. Like other tree squirrels, the red squirrel is diurnal and lives in forest areas. It feeds primarily on seeds and fruits from various trees, and occasionally insects and other animal foods such as bird eggs and young birds. Although the animals are frequently observed, very little information is available about their mating and reproductive behavior.
features
general characteristics
The colorful squirrel is a comparatively large tree squirrel with a long tail. With a head-trunk length of 22 to 34, usually 25 to 26.5 centimeters and a tail length of 23 to 33, usually 26 to 28 centimeters, the red squirrel is slightly larger than the Eurasian squirrel . The weight is about 430 to 900 grams. There is no sexual dimorphism between the two sexes in terms of color and size, but there may be large differences in size within regional populations as well as between the individual populations and subspecies.
The different subspecies of the colored squirrel show a very high variability in color and pattern, which otherwise only appears in this variety in the Asian Finlayson squirrel ( Callosciurus finlaysonii ) and partly in the North American fox squirrel ( Sciurus niger ). In the nominate form , all back areas and the base of the tail are yellowish gray, the belly and the feet are matt ocher. The back of the ears is pale rust-red and has a sand-colored basal spot. The upper side of the tail is black with white washings, the underside corresponds in its coloring to the back coloring and is bordered black and delimited whitish-gray against the upper side. In the case of the other subspecies, the tint of the fur on the back can vary from almost black or steel gray to red-brown, yellow-gray and even white. Sometimes the animals also have a large, light or dark spot on the back, which differs from the color of the sides of the body and the head. Animals with a rust-red neck, sides and legs also occur. The tail can be black with single white-tipped hairs or completely white hairs. In some forms, a change of coat occurs, which begins in April to May and is completed by October. After this, the animals usually appear lighter and more intensely colored, with black-backed animals the color can change to a chocolate brown.
The subspecies with the most intense and darkest hues ( S. v. Belti , S. v. Managuensis and S. v. Thomasi ) come at the same time in the regions with the heaviest rainfall in dense forest habitats from the tropical plains of the Caribbean coast to the eastern foothills of the central mountain regions. The also very dark S. v. atrirufus lives in rainy areas in Costa Rica. In drier and less densely forested Pacific coastal range on the other hand, some lighter forms (see S. v. Bangsi , S. dorsalis v. , P helveolus v. And S. goldmani v. ) With white ear patch and whitish belly.
Features of the skull and skeleton
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The measurements on the skulls of adult animals show a total length of 54.2 to 55.9 millimeters and a width in the area of the zygomatic arches of 34.3 to 35.4 millimeters, the size of the animals and thus also the skull dimensions vary depending on the subspecies and Region. The type has too a maxillary per half incisor tooth formed incisor (incisor) to which a tooth gap ( diastema follows). This is followed by two premolars and three molars . The teeth in the lower jaw correspond to those in the upper jaw, but only with a premolar. In total, the animals have a set of 22 teeth. As with body sizes, there is also great variability within the animals in the dimensions of the skull, which mainly affect the size of the individual bones and their relationship to one another. The size of the nasal bones and the curvature of the bony snout and forehead are particularly affected .
The penis bone (baculum), which is an important feature of the croissants for differentiating the species, corresponds in shape and length to that of various other related species such as the red-bellied squirrel, the collie squirrel and the Yucatan squirrel. It is about 11.5 to 12.5 millimeters long and at the broad base almost round in cross-section, from there it tapers to the tip to the narrowest point and then bends dorsally upwards. Here it widens into a round disc with a concave right and convex left side. Ventrally there is a groove in which the urethra lies. The female clitoral bone (Baubellum) is also typical of the species. It is about 4 millimeters long with a disc at the end that has a diameter of 2 millimeters.
Differentiation from other types
From other squirrels, with which it can match in body color, the species can be distinguished mainly by its tail color and its size. The red-tailed squirrel ( S. granatensis ), with which the red squirrel occurs in the southern part of the distribution area, has a bright red-colored tail. The red-bellied squirrel ( S. aureogaster ) in southern Mexico and Guatemala differs from the red-bellied squirrel in its lighter-colored feet, which are sand-colored black to black in the red-bellied squirrel and whitish with black speckles in the red-bellied squirrel in this region. Compared to Deppe's squirrel ( S. deppei ), Richmond's squirrel ( S. richmondi ) and also to the red-tailed squirrel, the red-tailed squirrel is also significantly larger with a significantly longer tail.
Distribution areas
The red squirrel lives in dry to moist forests in Central America and in southern Mexico . The distribution area extends from the southern part of the Mexican state Chiapas via Guatemala , El Salvador , Honduras , Nicaragua , Costa Rica to the southwestern half of Panama .
Way of life and ecology
Red squirrels are found in various forest habitats of tropical Central America, from dry coastal forests to humid inland rainforest areas. The habitats are usually home to various types of trees and shrubbery with portions of evergreen deciduous vegetation at altitudes of usually less than 1800 meters. In some regions of Costa Rica, however, the animals also occur at altitudes of up to 2600 meters. The animals are often tied to oak and pine forests ; in Mexico and Guatemala they live in lowland forests and also in fruit tree plantations and are less common in sunflower fields with isolated trees, parks and gardens. In Costa Rica in particular, the animals can also be found in agricultural plantations , especially in cocoa plantations.
The animals are diurnal and live as solitary animals on trees, but also leave them regularly to forage. The maximum activity is in the early morning, the rest of the time they spend mainly in their nests, which they build near the trunks in the branches of the trees, or in available tree hollows. Like other squirrels, the animals feed on a generalist and above all herbivorous diet , i.e. mainly eat parts of plants. The main part of their diet consists of seeds, nuts and fruits, the former being the most important source of food in large parts of the distribution area. Above all, they avoid particularly hard-shelled seeds and nuts, although acorns are consumed regularly. In addition, insects and other animal foods such as bird eggs and young birds are occasionally used as supplementary food. The animals probably make camps from seeds, but no observations have been made. For Mexico, especially the fruits and blossoms of the mangoes ( Mangifera indica ), guavas ( Psidium guajava ) and the yellow mombin plum ( Spondias mombin ) are documented as a source of food, whereby they eat the fruit without the seeds. The animals probably communicate with each other through deep sounds that are interpreted as alarm calls.
There is almost no information about the reproduction of the red squirrels, although the animals are frequent and can be observed. A seasonal breeding season from April to May is assumed for Panama, the number of young animals in a litter is probably around four to six animals.
Variegated squirrel come in their habitats sympatric with other squirrels occur and with these in competition for available habitats and food. In areas where they live together with the red-tailed squirrel ( S. granatensis ), they move to drier areas and become less demanding of their habitats. With the red-bellied squirrel ( S. aureogaster ), Deppe's squirrel ( S. deppei ) and Richmond's squirrel ( S. richmondi ), the red squirrel occurs at least in parts of the distribution area sympatric. Other squirrels of other genera that it can co- exist with are the Central American mountain squirrel ( Syntheosciurus brochus ) and the Central American miniature squirrel ( Microsciurus alfari ).
Like other squirrels, the red squirrels are preyed on by various predators, birds of prey and snakes. The Panama capuchin monkey ( Cebus imitator ), which hunts in groups and, in addition to other small vertebrates, also prey on squirrels, is one of the red squirrels' regular predators . According to studies in Costa Rica, squirrels represent around 25% of the monkeys' prey, another 25% are young white-nosed coatis ( Nasua narica ) and around 40% eggs and young birds.
So far only the tick Microtrombicula nicaraguae and the animal louse Enderleinellus hondurensis have been documented as ectoparasites . In captive animals also a was Borna virus with the label variegated squirrel-Borna virus 1 (Variegated Squirrel 1 Borna virus, VSBV-1) discovered that as a zoonosis a potentially fatal encephalitis can cause in humans.
Systematics
Taxonomy and phylogenetic position
The red squirrel is classified as an independent species within the squirrel ( Sciurus ), which consists of almost 30 species. The first scientific description comes from the Irish naturalist and then Honorary Secretary of the Zoological Society of London William Ogilby from 1839. He had it from Sir Edward Belcher , Captain of the Royal Navy and at that time with the HMS Sulfur on a world tour in the area of the coast South and Central America on the way, received for description. Ogilby only gave the "west coast of South America" as a place where the type was found, but they probably come from the area around San Carlos in the La Unión department in El Salvador. These were one of the first scientifically described Mammals of Central America, 1842 was Macroxus adolphei (now Sciurus variegatoides adolphei another subspecies of colored squirrel by) René Lesson from Nicaragua, together with the now considered synonymous to nominate considered Macroxus pyladei described.
There are no fossils of the red squirrel, the genus is dated to the Miocene . A close relationship with the red-bellied squirrel ( S. aureogaster ) is assumed due to the features of the skull and the coat pattern; it was also placed in the closer relationship of the Yucatan squirrel ( S. yucatanensis ) and the collie squirrel ( S. colliaei ).
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Systematics of the Central American Sciurus species according to Villalobos & Gutierrez-Espeleta 2014 *
*) Consideration of a limited number of species - not in the consideration group were e.g. the Yucatan croissant ( S. yucatanensis ) and the collie croissant ( S. colliaei ) |
By phylogenetic studies on the basis of molecular biological characteristics such as available sequence data of the ribosomal RNA (12S rRNA, 16S rRNA), mitochondrial CytB genes and the nuclear DNA of the IRBP genes and cytochrome b gene sequences a close relationship was the Central American squirrel species are confirmed within the squirrel. Accordingly, the red tail squirrel ( S. granatensis ) was identified as the sister species of the red squirrel with a very high degree of probability . The common sister species of these two species is the red-bellied squirrel ( S. aureogaster ) and these three species in common are in turn Deppe's squirrel ( S. deppei ). In the analysis, however, only a limited number of species was considered, not including the Yucatan squirrel and the collie squirrel. With this work, previous phylogenetic investigations from 2007 were confirmed, according to which the Central American tree squirrels form a separate family group compared to the North and South American species and thus the genus Sciurus is to be regarded as paraphyletic without the inclusion of Microsciurus and Syntheosciurus .
The scientific name variegatoides refers to the richness of color of the animals, which is also reflected in the English name "variegated squirrel" derived from it.
Subspecies
Within the species, fifteen subspecies are distinguished together with the nominate form :
- Sciurus variegatoides variegatoides (nominate form): The nominate form occurs in the tropical rainforests of the high elevations of Guatemala and the border area of Honduras and El Salvador and from there over eastern Honduras to the Pacific coast of eastern El Salvador.
- Sciurus variegatoides adolphei : The subspecies occurs in the lowlands around El Realejo in Nicaragua. The top of the head and the neck are iron gray, but lighter than the dark gray-brown back and the base of the tail. The tail is black on top with white washings. The belly side and the inside of the legs are reddish maroon, sometimes with white spots. It was described in 1842 under the name Macroxus adolphei by René Primevère Lesson and named after his brother Pierre Adolphe Lesson , who killed it in Nicaragua and sent it to him.
- Sciurus variegatoides atrirufus : This subspecies occurs in the region around Tambor on the Nicoya Peninsula in Costa Rica. It has a striking and wide black back band, which is bordered on the sides by cinnamon or red-brown fur, which also covers the belly side. There are no hard shoulders. The top of the head is also cinnamon-colored to rust-brown and the ears are outlined in black. Black eye stripes run over the eyes, which extend over the base of the ears and then merge into the black stripe on the back. The tail is black on top with white hair tips and chestnut brown on the underside. The subspecies was described by William P. Harris Jr. as Sciurus adolphei atrirufus .
- Sciurus variegatoides bangsi : The distribution area of this subspecies extends from the eastern part of Guatemala on the Pacific coast to western El Salvador. Its coloring largely corresponds to S. v. goldmani , but is lighter and grayer than the grayest variants of this subspecies and has no rust-red washings in the back fur. The ears are edged with black and often have a sand-colored or rust-red tuft of hair, and there is also a white basal spot. The feet are light gray with white toes, the underside is also white. The species was described by Donald R. Dickey , who named it after the American zoologist Outram Bangs .
- Sciurus variegatoides belti : This subspecies occurs in the humid rainforest areas from the west coast of Honduras to and inland from Nicaragua to Yoro in Honduras and Chontales and the Río San Juan in Nicaragua. The belly is a single color rust-red, the feet are speckled rust-red-yellow.
- Sciurus variegatoides boothiae : The distribution area of this form includes the rainforests in the northern part of Honduras around the city of San Pedro Sula and extends southeast to San Juan de Murra in the Nueva Segovia department in Nicaragua. The back is gray-brown with a glossy black wash, the feet black-gray. The belly of the animals is white. The ears are black, bordered with rust-red-black spots at the base. The animals have a pale rust-red stripe on the sides.
- Sciurus variegatoides dorsalis : This subspecies occurs in the comparatively dry regions around Lake Nicaragua in Nicaragua and in northwestern Costa Rica including the Nicoya Peninsula. The coloring of the animals is lighter and brighter than that of S. v. adolphei . The center line of the back is black-brown to grayish yellow-brown, surrounded by lighter fur, which can be sand-colored to whitish brown. The underside is white, yellowish sand-colored or light red-brown. The head color is lighter and paler than the back color.
- Sciurus variegatoides goldmani : This subspecies is named after the American zoologist and soldier Edward Alphonso Goldman and lives in the dry tropical forests from the coastal areas of southeastern Guatemala north to Chiapas, Mexico. The back of the animals is iron gray, the underside white. The ears are outlined in black and have reddish brown tufts of hair, behind the base of the ears there is a white spot. The tail is black with white washings. In Mexico the animals are usually dark brown to gray-brown with a darker neck and light postauricular spot, the tail is black with a white frost.
- Sciurus variegatoides helveolus : The distribution area of this subspecies extends in Panama from Panama City to Santiago de Veraguas . They equal the nominate form and S. v. dorsalis , the legs and the abdomen are lighter.
- Sciurus variegatoides loweryi : This subspecies occurs in the Valle del General and the Valle de Coto Brus in Costa Rica. The back of the animals is largely black, mixed with yellow-brown parts. The sides of the body and the belly are yellow-brown, as are the spots behind the ears (postauricular spots). The top of the tail is black with white parts. The underside of the tail has hairs that are brown at the base and have tan- yellow and black bands and a white tip. From S. v. dorsalis , it can be distinguished by its smaller size and the tan yellow, never white, postauricular spots. The subspecies was first described by the American zoologist Alvadus Bradley McPherson in 1971, and it is named after his university professor George H. Lowery .
- Sciurus variegatoides managuensis : The subspecies occurs in the humid rainforest area along the Managua in the Quiriguá area in Guatemala near the border with Honduras. The shape is smaller than S. v. boothiae , the back side is blackish yellow and the underside sand-colored yellow.
- Sciurus variegatoides melania : The subspecies occurs in the coastal flatlands of eastern Panama. She has an even, glossy black body color.
- Sciurus variegatoides rigidus : The subspecies lives from central Costa Rica to the Gulf of Nicoya . The back side is mottled black and ocher yellow to white. The hair is black with an ocher ring. The ventral side is rust-red with a white center line. The legs are rust-red with black parts.
- Sciurus variegatoides thomasi : The range of the subspecies includes the humid rainforests of central Costa Rica and the Caribbean coastal areas. The back is black with a brown translucent basal color. The underside is dark rust-colored, sometimes with white spots. The ears are blackish with tufts of black hair and behind them is a black basal patch. The subspecies was named after the British zoologist Oldfield Thomas .
- Sciurus variegatoides underwoodi : The subspecies occurs from El Caliche Cedros in Honduras south to Matagalpa in Nicaragua and on the Golfo Santa Elena in Costa Rica. The back color is gray-brown and corresponds to that of S. v. boothiae , however, is a little lighter. The underside is white. There are sand-colored postauricular spots behind the ears and the back line is also sand-colored. The legs and feet are dark ocher, sand or black.
Colorful squirrels of the subspecies S. v. atrirufus
Colorful squirrels of the subspecies S. v. dorsalis
Colorful squirrels of the subspecies S. v. loweryi in Costa Rica
Colored squirrels in Costa Rica
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Status, threat and protection
Threat and protection
The International Union for Conservation of Nature and Natural Resources (IUCN) classifies the red squirrel as Least Concern (LC). This is justified by the large distribution area and the frequent occurrence of the species in its distribution area. The species is also very adaptable to different habitats and habitat changes and occurs in several nature reserves. There are no potential threats to the entire stock; in the medium to long term, severe deforestation of habitats and their conversion into agricultural land could be classified as a risk. In Mexico the species is considered to be particularly protected by the Secretaría de Medio Ambiente y Recursos Naturales (SEMARNAT), but there is no particular threat here either.
Husbandry and zoonoses
Because of their color variations and behavior, red squirrels are sometimes kept as pets in North America and Europe, and they are also bred . Like other domestic animals, the animals are potentially carriers of pathogens. In the course of three deaths among breeders of red squirrels in Saxony-Anhalt between 2011 and 2013, the red squirrel Bornavirus 1 was discovered, a new Bornavirus that can cause potentially fatal encephalitis in humans. The Friedrich-Loeffler-Institut (FLI) was able to use metagenomic analysis to identify a matching gene sequence in a red squirrel from breeding and in tissue samples from the brains of the deceased breeders , which indicated the occurrence of the novel virus. No information is available about the origin of the virus, the epidemiology and the potential transmission routes of this zoonosis ; scratches or bite marks are assumed to be the likely transmission routes. In January 2016 it was announced that further infected animals could be identified in zoos and with private owners, including species of the beautiful squirrel (Callosciurinae).
supporting documents
- ↑ a b c d e f g h i j k l m n o p q r Sciurus variegatoides. In: Richard W. Thorington Jr., John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012, ISBN 978-1-4214-0469-1 , pp. 70-73 .
- ↑ a b K. Carr, P. Myers: Sciurus variegatoides . Animal Diversity Web, 2004.
- ↑ a b c d e f g h i j k l m Troy L. Best : Sciurus variegatoides. Mammalian Species 500, 1995, pp. 1-6. (Full text) ( Memento from September 2, 2016 in the Internet Archive )
- ↑ a b c d Variegated squirrel - Sciurus variegatoides. In: Don E. Wilson, TE Lacher, Jr., Russell A. Mittermeier (Eds.): Handbook of the Mammals of the World. Volume 6: Lagomorphs and Rodents 1. Lynx Edicions, Barcelona 2016, ISBN 978-84-941892-3-4 , p. 749.
- ↑ a b c Sciurus variegatoides in the IUCN Red List of Threatened Species 2016.1. Posted by: J. Koprowski, L. Roth, F. Reid, N. Woodman, R. Timm, 2008. Retrieved September 1, 2016.
- ↑ a b c d Variegated squirrel. In: Gerardo Ceballos: Mammals of Mexico . Johns Hopkins University Press, Baltimore MD 2014, ISBN 978-1-4214-0843-9 , pp. 184-185 .
- ^ Lisa M. Rose: Vertebrate Predation and Food-Sharing in Cebus and Pan. In: International Journal of Primatology. 18 (5), October 1997, pp. 727-765. doi: 10.1023 / A: 1026343812980
- ↑ a b New Bornavirus transmissible to humans. Information from the Friedrich Loeffler Institute (FLI), July 9, 2015; accessed on September 4, 2016.
- ^ A b Further cases of Variegated Squirrel 1 Bornavirus. In: fli.de. March 1, 2016, accessed August 9, 2019 .
- ↑ a b Bernd Hoffmann, Dennis Tappe, Dirk Höpe and others: A Variegated Squirrel Bornavirus Associated with Fatal Human Encephalitis. In: The New England Journal of Medicine. (N Engl J Med) Volume 373, 2015, pp. 154-16. doi: 10.1056 / NEJMoa1415627
- ↑ a b Sciurus (Sciurus) variegatoides . In: Don E. Wilson , DeeAnn M. Reeder (Eds.): Mammal Species of the World. A taxonomic and geographic Reference. 2 volumes. 3. Edition. Johns Hopkins University Press, Baltimore MD 2005, ISBN 0-8018-8221-4 .
- ^ William Ogilby : [no title]. In: Proceedings of the Zoological Society of London. pt. 7, 1839, p. 117. (full text)
- ^ A b René Primevère Lesson : Nouveau Tableau du Règne Animal: Mammifères. Paris 1842, pp. 112-113. (Full text)
- ^ A b Federico Villalobos, Gustavo Gutierrez-Espeleta: Mesoamerican tree squirrels evolution (Rodentia: Sciuridae): a molecular phylogenetic analysis. In: Revista de biologia tropical. (International Journal of Tropical Biology) 62 (2), pp. 649-657. (Full text)
- ↑ Federico Villalobos, Fernando A. Cervantes: Phylogenetic relationships of Mesoamerican species of the genus Sciurus (Rodentia: Sciuridae). In: Zootaxa. 1525, 2007, pp. 31-40. doi: 10.11646 / zootaxa.1525.1.3
- ^ William P. Harris Jr .: A new squirrel from Costa Rica. (= Occasional Papers of the Museum of Zoology. 219). October 15, 1930. (full text)
- ^ Donald R. Dickey: Five new mammals of the rodent genera Sciurus, Orthogeomys, Heteromys, and Rheomys, from El Salvador. In: Proceedings of The Biological Society of Washington. 41, 1928, pp. 7-13. (Full text)
- ↑ Alvadus Bradley McPherson: A new subspecies of the squirrel Sciurus variegatoides Ogilby from Costa Rica. In: Revista de biologia tropical. 19 (1, 2), 1971, pp. 191-194. (Full text)
- ↑ New Bornavirus discovered in red squirrels - possible connection with infections in humans. Information from the Robert Koch Institute in Berlin, July 9, 2015; accessed on September 4, 2016.
- ↑ Profile of Variegated squirrel 1 bornavirus (VSBV-1). Friedrich Loeffler Institute (FLI), March 1, 2016; accessed on September 4, 2016.
literature
- Sciurus variegatoides. In: Richard W. Thorington Jr., John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012, ISBN 978-1-4214-0469-1 , pp. 70-73 .
- Troy L. Best : Sciurus variegatoides. In: Mammalian Species . 500, 1995, pp. 1-6. (Full text)
- Variegated squirrel. In: Gerardo Ceballos : Mammals of Mexico . Johns Hopkins University Press, Baltimore MD 2014, ISBN 978-1-4214-0843-9 , pp. 184-185 .
- Variegated squirrel - Sciurus variegatoides. In: Don E. Wilson, TE Lacher, Jr., Russell A. Mittermeier (Eds.): Handbook of the Mammals of the World. Volume 6: Lagomorphs and Rodents 1. Lynx Edicions, Barcelona 2016, ISBN 978-84-941892-3-4 , p. 749.
Web links
- Sciurus variegatoides inthe IUCN Red List of Threatened Species 2016.1. Posted by: J. Koprowski, L. Roth, F. Reid, N. Woodman, R. Timm, 2008. Retrieved September 1, 2016.
- K. Carr, P. Myers: Sciurus variegatoides . Animal Diversity Web, 2004.
