Collie croissant
| Collie croissant | ||||||||||||
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Collie croissant, drawing from John James Audubon : The viviparous quadrupeds of North America. (1845-1848) |
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| Scientific name | ||||||||||||
| Sciurus colliaei | ||||||||||||
| Richardson , 1839 |
The collie squirrel ( Sciurus colliaei ) is a type of squirrel from the genus of squirrels ( Sciurus ). It occurs in western Mexico .
features
The collie croissant reaches a head-torso length of about 24.3 to 26.6 centimeters, plus a tail that is about 24.7 to 27.4 centimeters long. The weight of the animals ranges from about 330 to 440 grams. The back fur of the animals is usually dark gray mottled with yellowish washouts that extend to the base of the tail. The sides of the body are lighter gray, the belly is white to light orange. The top of the tail is black with white washouts, sometimes gray with yellow and white edges.
The animals have two upper premolars , only those in the northern part of the range sometimes have only one. Due to various features of the penis bone , the skull as well as the coat color and ecology, the collie squirrel was combined with the red-bellied squirrel ( S. aureogaster ), the red squirrel ( S. variegatoides ) and the Yucatan squirrel ( S. yucatanensis ) to form a species complex.
distribution
The collie croissant occurs in a narrow strip near the coast in western Mexico from the states of Sonora and Chihuahua to Sinaloa , Durango , Nayarit , Jalisco and Colima . The height distribution ranges from about 1290 m to 2190 meters.
Way of life
The collie squirrel lives in the dense tropical and subtropical vegetation of the coastal regions of the Pacific coast of Mexico, where various forest types are inhabited. Often it is highland oak forests and tropical dry forests (arroyo), in the north the species also lives in the subtropical canyons. Often figs (genus Ficus ) and palms of the genus Attalea , especially Attalea cohune , occur in the habitat. The species is diurnal and is most active in the morning and late afternoon. The squirrels are mainly arboreal, but occasionally also come to the ground. They feed mainly on the fruits and seeds of palm trees, figs and oaks in their habitat.
The nests ( Kobel ) are created in the outer branches of the trees; However, the squirrels also build nests in tree hollows or abandoned termite burrows. There is insufficient data on reproduction. It is assumed that the young are littered in March through April, but a female with a developing embryo was also caught in late May and June .
Three types of animal lice have been found parasites on the Collie squirrel: Enderleinellus mexicanus , Enderleinellus pratti and Neohaematopinus sciurinus . It occurs in the north of its distribution area sympatric with the Aberthörnchen ( S. aberti ) and the Mexican fox squirrel ( S. nayaritensis ), in the south with the Mexican fox squirrel and the red-bellied squirrel.
Systematics
The collie squirrel is classified as an independent species within the genus of squirrels ( Sciurus ), which consists of almost 30 species. The first scientific description comes from John Richardson from 1839, who described the species on the basis of individuals from San Blas and Tepic in the Mexican state of Nayarit.
Four subspecies are distinguished within the species, including the nominate form :
- Sciurus colliaei colliaei : nominate form in Nayarit.
- Sciurus colliaei nuchalis : In Jalisco and Colima. The subspecies has a yellowish neck and a black abdomen, the ears are more yellow or rusty red than in the nominate form.
- Sciurus colliaei sinaloensis : In Sinaloa. The skull is larger than that of the nominate form.
- Sciurus colliaei truei : In Sorora, Chihuahua and Sinaloa. The skull is wider and the cranial skull flatter than in the nominate form.
Status, threat and protection
The International Union for Conservation of Nature and Natural Resources (IUCN) classifies the Collie croissant as “least concern”. This is justified with the relatively large distribution area and the assumed high population numbers, which do not decrease so quickly that inclusion in a hazard category is justified.
The animals are hunted locally as meat suppliers. Potential causes of danger also lie in the deforestation of the habitats of the animals and it is assumed that the populations have declined by 6 to 8% in the last 15 years. The decline in populations and the downsizing of habitats are primarily due to the fragmentation of the forest areas, as the animals tend to be in closed vegetation. This could be demonstrated on the basis of the feeding traces on the fruits of Ceiba aesculifolia , which were detected on 100% of the trees in closed vegetation, but only on 34% in fragmented areas.
supporting documents
- ↑ a b c d e f g h i j 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. 47-49 .
- ^ A b Troy L. Best : Sciurus colliaei. Mammalian Species 497, June 23, 1995 ( full text )
- ↑ a b c d Sciurus colliaei in the IUCN Red List of Threatened Species 2015.1. Posted by: PC de Grammont, A. Cuarón, E. Vázquez, 2008. Retrieved September 6, 2015.
- ↑ a b Sciurus colliaei In: Don E. Wilson , DeeAnn M. Reeder (Ed.): 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 .
literature
- 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. 47-49 .
- Troy L. Best : Sciurus colliaei. Mammalian Species 497, June 23, 1995 ( full text )
Web links
- Sciurus colliaei inthe IUCN Red List of Threatened Species 2015.1. Posted by: PC de Grammont, A. Cuarón, E. Vázquez, 2008. Retrieved September 6, 2015.