Sun squirrel
| Sun squirrel | ||||||||||||
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Sun squirrel in Ghana |
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| Scientific name | ||||||||||||
| Heliosciurus | ||||||||||||
| Trouessart , 1880 |
The sun squirrels ( Heliosciurus ) are a genus of tree-living squirrels in African forests. They bear their name because they like to lie in the sun on the highest branches of the trees.
features
The sun squirrels are medium-sized to large types of squirrels with head and trunk lengths of 17 to 27 centimeters, plus a tail that is 15 to 30 centimeters long . They are therefore larger than the species of the redshank squirrels ( Funisciurus ) and the African dwarf squirrels ( Myosciurus ), but larger than the species of the African palm squirrels ( Epixerus ) and the oil palm squirrels ( Protoxerus ). They are narrowly built and have a long, slender tail, which is usually a little longer than the body. Depending on the species, they have a gray to brown or black-brown, in some species also reddish to red-brown, coat color with light speckles and without back stripes, the underside is whitish, yellowish or reddish brown. The head is comparatively small, the ears are short and close to the head. The legs are relatively long. The tail is covered with long hair and more or less clearly banded with light and dark rings. The females have three pairs of teats , the males have no penis bones (bacculus).
| 1 | · | 0 | · | 1 | · | 3 | = 20 |
All the species other than the Ruwenzori sun squirrel ( Heliosciurus ruwenzorii ) have a a maxillary per half incisor tooth formed incisor (incisor) to which a tooth gap ( diastema follows). This is followed by a premolar and three molars . The teeth in the lower jaw correspond to those in the upper jaw. In total, the animals have a set of 20 teeth. The Ruwenzori sun squirrel has an additional third, very small, premolar in the upper jaw.
Way of life
Sun squirrels are crepuscular tree dwellers. Occasionally they also come to the forest floor, but quickly climb a tree the first time they are disturbed. They flee from danger to the treetops. They seek protection in tree hollows, where they also build their nests, mostly from leaves. Although they generally live solitary, they are not aggressive towards conspecifics and tolerate their proximity. Warning calls and whistles that are emitted when there is danger speak for a more networked social behavior. The number of young in a litter is from one to five.
Like most tree-dwelling squirrels, sun squirrels eat nuts, seeds and fruits, and occasionally insects and bird eggs. The enemies of the sun squirrels are small tree-dwelling predators such as genets and pardle rollers . Young squirrels also often fall prey to rats, snakes, and driver ants . The mother animal closes the entrance to its cave with twigs, which is usually insufficient protection. When an ant migration approaches, the mother tries to bring the young to a safe place in the mouth.
Systematics
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Phylogenetic systematics of Protoxerini according to Mercer & Roth 2003
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The sun squirrels form their own genus within the ground squirrels (Xerinae) and are assigned to the tribe Protoxerini together with several other genera , all of which are native to sub-Saharan Africa. The genus was first described by Édouard Louis Trouessart in 1880, who selected the gray-footed squirrel, first described by William Ogilby as Sciurus gambianus in 1835, as the type species for the genus and thus separated it from the genus Sciurus .
As part of a molecular biological investigation of the phylogeny of the squirrels, the sun squirrels within the Protoxerini were identified as the sister group of a common taxon made up of the oil palm squirrel ( Protoxerus ), the African palm squirrel ( Epixerus ebli ), the redshank squirrel ( Funisciurus ) and the African bush squirrel ( Paraxerus ). The African miniature squirrel ( Myosciurus pumilio ) is compared to the entire taxon as the most primitive species.
Six types are distinguished within the genus:
- Gray footed squirrel , Heliosciurus gambianus ( Ogilby 1835 ), West, Central and East Africa
- Variable sun squirrel , Heliosciurus mutabilis ( Peters , 1852 ), East Africa
- Little sun squirrel , Heliosciurus punctatus ( Temminck , 1853 ), Liberia , Ivory Coast , Ghana
- Red-footed sun squirrel , Heliosciurus rufobrachium ( Waterhouse , 1842 ), West, Central, and East Africa
- Ruwenzori Sun Squirrel , Heliosciurus ruwenzorii ( Schwann , 1904 ), Ruwenzori Mountains
- Zanj Sun Squirrel , Heliosciurus undulatus ( True , 1892 ), Kenya , Tanzania
The lesser sun squirrel is often considered a subspecies of the gray footed squirrel . Many of the species are very variable. The gray-footed squirrel comes in at least seven subspecies, all of which have completely different coat colors. What a subspecies and what a species is is often controversial in individual cases. Instead of naming a number of species, Grzimek's animal life speaks of 52 different "forms" in this genus.
supporting documents
- ^ A b c Peter Grubb: Genus Heliosciurus, Sun Squirrels. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume III. Rodents, Hares and Rabbits. Bloomsbury, London 2013, pp. 61-62; ISBN 978-1-4081-2253-2 .
- ^ A b John M. Mercer, V. Louise Roth: The Effects of Cenozoic Global Change on Squirrel Phylogeny. Science 299, 2003; Pp. 1568-1572; doi : 10.1126 / science.1079705
literature
- Peter Grubb: Genus Heliosciurus, Sun Squirrels. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume III. Rodents, Hares and Rabbits. Bloomsbury, London 2013, pp. 61-62; ISBN 978-1-4081-2253-2 .
- Ronald M. Nowak: Walker's Mammals of the World. 2 volumes. 6th edition. Johns Hopkins University Press, Baltimore MD et al. 1999, ISBN 0-8018-5789-9 .
