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| Rio Grande ground squirrel | |
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Scientific classification 
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| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Rodentia |
| Family: | Sciuridae |
| Genus: | Ictidomys |
| Species: | I. parvidens
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| Binomial name | |
| Ictidomys parvidens (Mearns, 1896)
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| Synonyms | |
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The Rio Grande ground squirrel (Ictidomys parvidens) is a species of squirrel in the family Sciuridae. It is found in the southwestern United States (Texas and New Mexico) and in northeastern Mexico.
Description
[edit]The Rio Grande ground squirrel is predominantly brown with nine broken rows of squarish white spots on its back.[1] Its spotting is less distinct than the spotting on the thirteen-lined ground squirrel.[2] It varies in body length from 29.9 centimetres (11.8 in) to 35.2 centimetres (13.9 in)[1]
Distribution and Habitat
[edit]The Rio Grande ground squirrel is found in grasslands and scrub habitat from southwestern New Mexico to northern Zacatecas and east to the gulf coast.[1] In western Texas, it is often associated with mesquite and cholla.[1]
While much of its original habitat has been destroyed by humans, it has adapted well to human civilization and can now be found on golf courses and other grassy areas such as the sides of highways.[1] Each squirrel normally has more than one burrow and each of them have as many as five escape tunnels.[1] The tunnels are not marked by a mound of dirt on top. Most burrows have a sleeping chamber for the offspring which is lined with grasses.[1]
Diet
[edit]The Rio Grande ground squirrel is omnivorous. Its diet includes seeds, nuts, grains, roots, bulbs, plant stems, leaves, mice, insects, and eggs.[1] It often stores seeds, grains, and nuts in its cheeks pouches and takes them back to its den to eat later. In the summer it eats insects. It has also been documented eating roadkill.[1]
Reproduction and hibernation
[edit]The mating season of the Mexican ground squirrel lasts from April to mid July, with a peak in May.[3] Females can mate after their first season of hibernation.[3] It is common for most Mexican ground squirrels to hibernate, but there have been cases where they have not.[3] The species is normally solitary, but come together in groups during the mating season.[3] It has been found that female hormone levels change during this period to allow the coming together of groups without aggression.[3] During the mating season, The female will prepare a nesting chamber in her burrow and line it with mesquite and grass. The average litter size is five, but can range from one to ten.[3] The young are born toothless, without fur, and will stay with their mother for three months before leaving to live on their own.[3]
Taxonomy and systematics
[edit]The Rio Grande ground squirrel was historically considered a subspecies of the Mexican ground squirrel and, along with the other species of the genus Ictidomys, was classified in the much larger genus Spermophilus.[4] DNA sequencing of the cytochrome b gene showed that this group was paraphyletic to the prairie dogs and marmots, leading to the separation of Ictidomys. [5] [2] The Rio Grande ground squirrel was separated from the Mexican ground squirrel due to its smaller body size and disjunct range.[2]
The Rio Grande hybridizes with the thirteen-lined ground squirrel in western Texas and southeastern New Mexico.[6]
References
[edit]- ^ a b c d e f g h i Young, Carole J.; Knox Jones, Jr., J. "Mammalian Species Spermophillus Mexicanus". doi:10.2307/3503778. JSTOR 3503778.
- ^ a b c Helgen, Kristofer M.; Cole, F. Russel; Helgen, Lauren E.; Wilson, Don E (2009). "Generic Revision in the Holarctic Ground Squirrel Genus Spermophilus" (PDF). Journal of Mammalogy. 90 (2): 270–305. doi:10.1644/07-MAMM-A-309.1. S2CID 28483038. Archived from the original (PDF) on 2013-10-04. Retrieved 2013-07-18.
- ^ a b c d e f g Mandier, Valérie; Gouat, Patrick (September 1996). "A laboratory study of social behaviour of pairs of females during the reproductive season in Spermophilus spilosoma and Spermophilus mexicanus". Behavioural Processes. 37 (2–3): 125–136. doi:10.1016/0376-6357(95)00078-X. PMID 24897437.
- ^ Wilson, D. E.; Reeder, D. M., eds. (2005). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. ISBN 978-0-8018-8221-0. OCLC 62265494.
- ^ Herron, Matthew D.; Castoe, Todd A.; Parkinson, Christopher L. (2004). "Sciurid phylogeny and the paraphyly of Holarctic ground squirrels (Spermophilus)". Molecular Phylogenetics and Evolution. 31 (3): 1015–30. Bibcode:2004MolPE..31.1015H. doi:10.1016/j.ympev.2003.09.015. PMID 15120398.
- ^ Cothran, Gus E. (1983-11-25). "Morphologic Relationships of the Hybridizing Ground Squirrels Spermophilus mexicanus and S. tridecemlineatus". Journal of Mammalogy. 64 (4): 591-602. doi:10.2307/1380514.
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No page comments added.Synonyms
- Ictidomys mexicanus
- Mexican Ground-Squirrel