Gray squirrel
Gray squirrel | ||||||||||||
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![]() Gray squirrel ( Sciurus carolinensis ) |
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Scientific name | ||||||||||||
Sciurus carolinensis | ||||||||||||
Gmelin , 1788 |
The gray squirrel ( Sciurus carolinensis ) is an originally North American rodent - species from the family of squirrels (Sciuridae) and the genus of squirrels (Sciurus). It was naturalized in several places in Europe and largely displaced, especially in the British Isles , the native Eurasian squirrel .
features
The species is similar to the squirrel , but has a gray coat. The tint can vary between a light silver-gray and a very dark black-gray. A reddish color occurs, but is rare. With a head-trunk length of 30 centimeters, a tail length of 20 centimeters and a weight of 400 to 710 grams, the gray squirrel is slightly larger than its European relative. It is easy to distinguish in winter by the fact that it does not have any tufts of hair on the ears (“brush”) typical of squirrels. Another distinguishing feature are the white edges of the tail, which are always missing in squirrels.
Way of life
The gray squirrel actually has its home in the forest, where it finds shelter from enemies in the undergrowth, but it can also be found in parks and gardens in many places. It builds its nest (also called Kobel) either in the branches of trees or in hollow tree trunks; it is laid out with soft material such as moss, dry grass and feathers.
Gray squirrels are omnivores. They feed mainly on seeds and buds of all kinds, especially those of the spruce , beech , larch and birch , as well as tree bark and mushrooms when no other food sources are available in the winter months. In addition, they sometimes eat insects , frogs , young birds and bird eggs and bones ; even cannibalism occurs. They create winter hiding places with food that they later find using their sense of smell and memory.
Reproduction and rearing of young
The sexual maturity of the European squirrel begins at one year. Reproduction is very similar to that of the European squirrel. There are two litters, or three litters if the conditions are favorable, as there are no tight mating seasons. However, cubs are very unusual between September and December. The couples do not stay together for life. The males have no part in raising the young; they leave the female after mating, while the female then takes care of building the nest. The gestation period of the females varies between 42 and 45 days; up to seven young are born per litter. The young are naked and blind after birth and need to be suckled every three to four hours for the first few weeks. They leave the nest for the first time at around seven weeks old to playfully learn the skills they will need as adults. Little by little, the young get used to solid food and are finally weaned at around ten weeks of age, until they finally leave their maternal nest around a month later.
distribution
The distribution area includes the eastern half of the United States and southeastern Canada . The gray squirrel is extremely common here. It was also introduced by humans in Great Britain , Ireland and Italy , with sometimes catastrophic consequences for the squirrel , which has almost become extinct in Great Britain due to competition from the gray squirrel. Something similar is emerging in Italy, and the gray squirrel is expected to spread further to Central Europe over the next few decades. Animals are also said to have been released very "successfully" in South Africa .
The western gray squirrel lives in the western United States ; to distinguish it from this, the species described here is also referred to as the "eastern gray squirrel".
Naturalization in England
In 1889 the first 350 gray squirrels were released in the English county of Bedfordshire . In the following period there were further naturalization campaigns . The animals settled in so well that the population in England steadily expanded and today consists of several million specimens. Due to the spread, however, the native squirrel has been and is being displaced from its habitat and is now rarely found on the island. Attempts to exterminate the gray squirrels were unsuccessful. The reasons for these control measures were the damage caused by the gray squirrels, especially in oak and beech forests; they peel the bark from young trees. The decline in songbird populations due to food competition is also attributed to the gray squirrels. In the 1960s, the number of gray squirrels did not seem to increase any further. A coexistence with the British subspecies of the European squirrel seemed thus to be possible under certain conditions, even if only by niche formation . The larger and stronger gray squirrels inhabit the deciduous forests of the lowlands, while there are more squirrels in the mountains with a cooler climate and mainly coniferous forests. But the two ecologically very similar species cannot syntopically coexist in the long term. This is probably not possible because of the constant struggle for food and nesting places. A habitat can only be colonized by one of the species.
According to an Irish study, a sufficient population of pine marten can prevent the European red squirrels from being displaced by the gray squirrel. Scientists suspect that European squirrels are comparatively safer from the pine marten because they are more agile than the gray squirrels and spend less time on the ground to eat.
Parapox virus
The rapid decline of the European squirrels and the simultaneous expansion of the gray squirrels in common areas of occurrence - especially in Great Britain - is also said to be due to a parapox virus ( parapox virus of the squirrels ). The so-called "squirrel pox" cause a high mortality rate among red squirrels, while the gray squirrels are immune to the pathogen they have brought in. The virus is likely to be transmitted primarily through successive use of the same nest. Since there are neither vaccines nor remedies for the disease, these findings support the demand for special "squirrel reserves" that are kept free of gray squirrels.
The gray squirrel was added to the “List of Unwanted Species” for the European Union in 2016.
Systematics
The gray 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 Carl von Linné from 1758 in his 10th edition of the Systema naturae described. The former colony Carolina in North America is given as the type locality .
Within the species, five subspecies are distinguished with the nominate form :
- Sciurus carolinensis carolinensis : nominate form
- Sciurus carolinensis extimus
- Sciurus carolinensis fuliginosus
- Sciurus carolinensis hypophaeus
- Sciurus carolinensis pennsylvanicus
Others
The gray squirrels are much less shy than European squirrels. When fishing for croissants , this is used to the extent that the animals can be attracted to a longer line with a peanut or other bait. It is even possible to carefully lift the animal until it hovers above the ground. The somewhat bizarre leisure activity began at an American campus university, presumably Harvard , and has spread from there.
In the UK, the Save Our Squirrels campaign was launched in 2006 to protect the European red squirrel from the gray squirrel by encouraging people to eat the latter. These are now also offered in restaurants and prepared by TV chefs. The US Environmental Protection Agency approved the gray squirrel for consumption in New Jersey in 2008 .
In Germany, gray squirrels may not be bred, offered, given or kept in stock by private individuals. The importation and keeping of gray squirrels is also prohibited in Switzerland.
The gray squirrel Tommy Tucker became famous in the United States in the 1940s for appearing in custom women's clothing.
A first count in October 2018 recorded 2,373 gray squirrels in Central Park in central Manhattan , New York City .
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. 45-47 .
Web links
- Sciurus carolinensis in the endangered Red List species the IUCN 2008. Posted by: AV Linzey, J. Koprowski, NatureServe, 2008. Accessed on January 1 of 2009.
- Report on stern.de about the spread of the gray squirrel in England and the displacement of the squirrel
Individual evidence
- ↑ a b animaldiversity.ummz.umich.edu
- ↑ Red squirrel finds pine marten a fearsome ally in its fight for survival. The Guardian, February 22, 2013, accessed November 21, 2015 .
- ^ Peter Lurz, Institute for Research on Environment and Sustainability at Newcastle University. In: Reserves for the Reds . In: Der Spiegel . No. 35 , 2006, pp. 130 ( online ).
- ↑ List of Invasive Alien Species of Union Concern (PDF) accessed on July 15, 2016
- ↑ a b c Sciurus carolinensis 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 .
- ^ Richard W. Thorington Jr. , John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012; Pp. 45-47. ISBN 978-1-4214-0469-1
- ↑ Julia S. Chen: More to Squirrels at Harvard? , The Harvard Crimson, April 23, 2009
- ↑ Harvard Squirrel Archives
- ↑ Marion Topitschnig: Eat squirrels - save squirrels. In: Kurier (daily newspaper) . November 1, 2009, accessed January 17, 2013 .
- ↑ Marlena Player: Saving a Squirrel by Eating One . In: New York Times . January 7, 2009, p. D1 ( online version ).
- ↑ The Economist, Vol. 402 Number 8772; "Wild meat: Squirrel nutcase"
- ↑ Squirrels released for the saucepan . In: RP Online , October 31, 2007
- ↑ Squirrels released for consumption in New Jersey. In: Berliner Morgenpost . June 10, 2008, accessed October 29, 2009 .
- ↑ § 3 of the Federal Species Protection Ordinance
- ↑ Ordinance on Hunting and the Protection of Wild Mammals and Birds, Appendix 2
- ↑ First counted: 2373 squirrels in Central Park , zeit.de from June 22, 2019