Franklin ground squirrel
| Franklin ground squirrel | ||||||||||||
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Franklin ground squirrel |
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Poliocitellus | ||||||||||||
| AH Howell , 1938 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Poliocitellus franklinii | ||||||||||||
| ( Sabine , 1822) |
The (or the) Franklin ground squirrel ( Poliocitellus franklinii , syn .: Spermophilus franklinii ) is a rodent from the squirrel family (Sciuridae). He lives in North America .
features
The Franklin ground squirrel has a brownish-gray fur with light and dark spots. It is light on the sides, thinner and whitish-yellow on the belly, and black with light spots on the tail. The hair on the head is usually more gray than on the rest of the body.
The average total length of the Franklin ground squirrel is 384.8 mm. The tail is 135.5 mm long on average. Females are slightly smaller (377.2 mm). The skull is up to 56.2 mm long at its widest point, the zygomatic arch enlarges posteriorly . The weight of the Franklin ground squirrel depends on gender and time of year. Males are 6 to 25 percent heavier than females. In spring the males weigh about 326 to 500 grams, in autumn 590 to 950 grams.
With its elongated physique, the Franklin ground squirrel is similar to the Richardson ground squirrel , but is slimmer and has a shorter, less bushy tail. It can be distinguished from the Columbia ground squirrel by its rust-colored fur and somewhat more robust body. It also resembles the gray squirrel , but is smaller, has a less bushy tail, smaller eye relief, shorter, rounder ears, longer claws, and a yellowish shade of fur on the croup .
distribution
The oldest existing fossils of Spermophilus franklinii come from the late Irvingtonian , a period of the North American mammal fauna (approx. 1,800,000-240,000 years BP ). Findings along Elm Creek in Beaver County , Oklahoma , suggest that the Franklin ground squirrel was part of the local fauna there 11,410 years ago during the late Pleistocene .
The Franklin ground squirrel is currently found in the centrally located states of the United States such as Kansas , Missouri , Illinois (north and center), Indiana (northwest), Nebraska , Iowa , North Dakota , South Dakota , Minnesota, and Wisconsin (south), but also on the southern Canadian plains including the prairie provinces of Manitoba , Saskatchewan and central Alberta .
In 2008 the species was downgraded from “Vulnerable” to “Near Threatened” in the Red List of Endangered Species because it is widespread and stocks are relatively secure in some areas, even if they are lost in other areas Habitat have been decimated. In particular, the populations in the USA are often very small and scattered, while in Canada the conditions for the Franklin ground squirrel are better, as there are still large contiguous habitats in some cases.
habitat
The Franklin ground squirrel's preferred habitat are meadows with tall grass, while avoiding mowed or grazed areas. He prefers thick, coarse grasses. The Franklin ground squirrel often lives on the border between forest and prairie . Often it can also be found in meadows that border roads or railroad tracks, as long as the grass is high enough.
Way of life
behavior
The Franklin ground squirrel lives in burrows that are around half a meter below the surface of the earth. Several nesting chambers lined with dried plant parts are connected to one another by a complex tunnel system. Some of the 8 cm high tunnels lead to dead ends, some of which serve as storage for food or excrement. Typically there are two to three exits to escape enemies. The Franklin ground squirrel often digs its burrows on steep slopes, which improves drainage.
The Franklin ground squirrel hibernates from August to April , and several individuals can sleep in one burrow. On average, males start hibernating more quickly than females, and adults more so than young ones, as the latter need more time to accumulate the necessary body fat. In the middle of April to the beginning of May the males come out of the burrows and establish a hierarchy among themselves. The females appear one to two weeks later. During the mating season, males and females sometimes live together in a burrow, after which the male leaves the burrow and lives as a loner. Some individuals move to another den three or four times during the time of the year that they are active above ground.
The Franklin ground squirrel is diurnal . It comes to the surface between 7 and 9 a.m., and returns to its building between 7 and 9 p.m. After sunset, it is very rarely seen outside the building. Occasionally he climbs on low bushes, sometimes trees. During the day he moves about 153 to 213 meters, whereby the joy of movement decreases before hibernation and during pregnancy.
The Franklin ground squirrel lives alone or in pairs. It is the least social of its kind. Individuals tend to avoid contact with one another; in captivity they react with growls and threatening gestures at their fellow species. The males sniff females on the back or anus and touch their noses with their own, but overall such olfactory examinations are more than five times less common than with other species of the genus Spermophilus .
Reproduction
In spring, when the females come out of the burrows after hibernation, the mating season begins . It ends in early June. During this period, reproductive males have enlarged testicles and sperm in the epididymis . This does not apply to young animals (yearlings), and females do not reproduce at this age either. An average of seven young are born 28 days after conception. You are initially naked and blind. The first hairs appear after nine days and the fur is fully developed after 16 days. After seven days, the lower incisors will show up. After 18 to 20 days, the eyes open. The young are suckled for 28 to 30 days.
Females live to be 4 to 5 years old, while males are only 1 to 2 years old.
nutrition
The Franklin ground squirrel is omnivorous . The proportion of plant and animal food varies with the seasons. In the spring it feeds mainly on plants, while it mainly eats animal food in the summer. Seeds and fruits are added in late summer. The Franklin ground squirrel seldom drinks water, but instead uses succulents to cover its fluid needs .
In addition to the roots of succulents, the vegetable menu of the Franklin ground squirrel includes, among other things, the leaves, buds and flowers of dandelions , goose thistles , great nettles , white clover , seeds and pods of flat peas and the berries of Virginian bird cherry and red elder . The Franklin ground squirrel also eats garden plants such as carrots, tomatoes, beans and potatoes. With a corresponding supply, animals make up a quarter of its food. These include insects (e.g. ants, crickets and grasshoppers), frogs, fish, bird eggs as well as young birds, mice and rabbits.
Predators and parasites
The most important predator is the silver badger , but the Franklin ground squirrel also serves as food for coyote , long-tailed weasel , American mink , red fox , ermine , striped skunk as well as hawks and snakes .
The Franklin ground squirrel is attacked by external parasites such as lice (mainly Enderleinellus suturalis ), fleas ( Opisocrostis bruneri ), mites ( Androlaelaps fahrenholzi ) and ticks ( Ixodes sculptus ). In a study in Manitoba , almost three quarters of all adults and all juveniles suffered from Opisocrostis bruneri . The infestation is particularly strong at the beginning of May and at the end of August, when the Franklin ground squirrel has not yet completely shed its thick winter fur or it is forming again.
The Franklin ground squirrel sometimes falls ill with pulmonary adiaspiromycosis , a lung disease that is triggered by inhaled spores of the fungus Emmonsia crescens . He also included a host of different internal parasites such as coccidia (z. B. Eimeria bilamellata , Eimeria callospermophili and Eimeria spermophili ), tapeworms (mainly Hymenolepis Citelli ), flukes ( Alaria mustelae ) and nematodes ( Physaloptera spinicauda ).
Taxonomy
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Phylogenetic systematics of the Marmotini according to Herron et al. 2004
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The Franklin ground squirrel is the only species in the genus Poliocitellus . The first description was in 1822 as Arctomys franklinii , five years later it was first referred to as Spermophilus franklini (Lesson). The species was named after the British naval officer and polar explorer John Franklin , who also gathered a lot of scientific information during his search for the Northwest Passage . For a long time it was classified as part of the ground squirrel and in it as a subgenus Poliocitellus , but after a comprehensive molecular biological investigation it was considered as an independent genus together with several other genera.
Genetic testing of a population in Minnesota showed that the Franklin ground squirrel had a diploid set of 42 chromosomes . The karyotype has 10 metacentric (i.e. centromere is central), 16 submetacentric (centromere between middle and end), and 14 acrocentric (centromere near end) autosomes . The X chromosome is medium-sized and submetacentric, the Y chromosome is very small and also submetacentric. By means of a DNA sequencing of the cytochrome -b it could be proven that the Franklin ground squirrel is genetically close to the thirteen-lined squirrel and the spotted squirrel .
literature
- Richard W. Thorington Jr., John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012; Pp. 296-298. ISBN 978-1-4214-0469-1
- Andrea C. Ostroff, Elmer J. Finck: Spermophilus franklinii. In: Mammalian Species . No. 724, July 30, 2003, pp. 1-5. ( PDF ).
Individual evidence
- ↑ a b Richard W. Thorington Jr., John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012; Pp. 296-298. ISBN 978-1-4214-0469-1
- ↑ a b c d e f Andrea C. Ostroff, Elmer J. Finck: Spermophilus franklinii. In: Mammalian Species. No. 724, 2003, p. 1.
- ↑ Spermophilus franklinii in the Red List .
- ↑ a b c d e f g Andrea C. Ostroff, Elmer J. Finck: Spermophilus franklinii. In: Mammalian Species. No. 724, 2003, p. 4.
- ↑ a b c d e Andrea C. Ostroff, Elmer J. Finck: Spermophilus franklinii. In: Mammalian Species. No. 724, 2003, p. 3.
- ↑ Andrea C. Ostroff, Elmer J. Finck: Spermophilus franklinii. In: Mammalian Species. No. 724, 2003, p. 2.
- ^ A b Matthew D. Herron, Todd A. Castoe, Christopher L. Parkinson: Sciurid phylogeny and the paraphyly of holarctic ground squirrels (Spermophilus). Molecular Phylogenetics and Evolution 31, 2004; Pp. 1015-1030. ( doi : 10.1016 / j.ympev.2003.09.015 , full text , PMID 15120398 )
- ↑ Kristofer M. Helgen, F. Russell Cole, Lauren E. Helgen, Don E. Wilson: Generic Revision in the holarctic ground squirrels genus Spermophilus. Journal of Mammalogy 90 (2), 2009; Pp. 270-305. doi : 10.1644 / 07-MAMM-A-309.1
