Thirteen-lined ground squirrel
|Thirteen-lined ground squirrel|
The thirteen-lined ground squirrel (Ictidomys tridecemlineatus), also known as the striped gopher, leopard ground squirrel, squinney, (formerly known as the leopard-spermophile in the age of Audubon), is a ground squirrel that is widely distributed over grasslands and prairies of North America.
It is brownish, with 13 alternating brown and whitish longitudinal lines (sometimes partially broken into spots) on its back and sides, creating rows of whitish spots within dark lines.
|Length||6¾–11⅝ inches (170–297 mm)|
|Tail||2⅜–5¼ inches (60–132 mm)|
|Head||1–1⅝ inches (27–41 mm)|
|Weight||3⅞–9½ oz (110–270 g)|
This species has usually been placed in the genus Spermophilus with about 40 other species. As this large genus is paraphyletic to prairie dogs, marmots, and antelope squirrels, Kristofer Helgen and colleagues have split it into eight genera, placing the thirteen-lined ground squirrel in Ictidomys with two other species.
The thirteen-lined ground squirrel is strictly diurnal and is especially active on warm days. A solitary or only somewhat colonial hibernator, it often occurs in aggregations in suitable habitats.
In late summer, it puts on a heavy layer of fat and stores some food in its burrow. It enters its nest in October (some adults retire much earlier), rolls into a stiff ball, and decreases its respiration from between 100 and 200 breaths per minute to one breath about every five minutes. It emerges in March or early April.
The burrow may be 15 to 20 feet (4.6 to 6.1 metres) long, with several side passages. Most of the burrow is within one to two feet (about half a meter) of the surface, with only the hibernation nest in a special deeper section. Shorter burrows are dug as hiding places. This ground squirrel's home range is two to three acres (0.8 to 1.2 ha).
Its primary diet includes grass and weed seeds, caterpillars, grasshoppers, and crickets, but it may also eat mice and shrews; it will viciously attack and consume cicadas if able to catch them. This squirrel sometimes damages gardens by digging burrows and eating vegetables, but also devours weed seeds and harmful insects.
It is well known for standing upright to survey its domain, diving down into its burrow when it senses danger, then sometimes poking out its nose and giving a bird-like trill. The "trill" is an alarm call that is most often used by females to warn nearby relatives. It has a maximum running speed of 8 mph (13 km/h) and reverses direction if chased.
Thirteen-lined ground squirrels can survive in hibernation for over six months without food or water and special physiological adaptations allow them to do so. During torpor, these squirrels maintain hydration by redistributing and storing osmolytes like sodium, glucose, and blood urea nitrogen in different body compartments (to be identified). When they enter a transient active-like state, small periods of arousal where these squirrels return to an active-like state temporarily, osmolarity and antidiuretic hormone levels rise while thirst remains suppressed.  Thirteen-lined ground squirrels also suppress the cell cycle and control the expression of cell cycle regulators in the liver during hibernation to conserve energy. During their active-like state, they are able to resume their cell cycle.
- Cassola, F. (2016). "Ictidomys tridecemlineatus". IUCN Red List of Threatened Species. 2016: e.T42564A22263122. doi:10.2305/IUCN.UK.2016-3.RLTS.T42564A22263122.en. Retrieved 13 November 2021.
- Helgen, Kristofer M.; Cole, F. Russel; Helgen, Lauren E. & Wilson, Don E (2009). "Generic Revision in the Holarctic Ground Squirrel Genus Spermophilus". Journal of Mammalogy. 90 (2): 270–305. doi:10.1644/07-MAMM-A-309.1.
- Schwagmeyer, P. L. (1980). "Alarm Calling Behavior of the Thirteen-Lined Ground Squirrel, Spermophilus tridecemlineatus". Behavioral Ecology and Sociobiology. 7 (3): 195–200. doi:10.1007/BF00299364. hdl:2027.42/46905. JSTOR 4599327. S2CID 23619096.
- Feng, Ni Y.; Junkins, Madeleine S.; Merriman, Dana K.; Bagriantsev, Sviatoslav N.; Gracheva, Elena O. (2019-09-23). "Osmolyte Depletion and Thirst Suppression Allow Hibernators to Survive for Months without Water". Current Biology. 29 (18): 3053–3058.e3. doi:10.1016/j.cub.2019.07.038. ISSN 0960-9822. PMC 6759396. PMID 31495581.
- Wu, Cheng-Wei; Storey, Kenneth B. (2012-05-01). "Pattern of cellular quiescence over the hibernation cycle in liver of thirteen-lined ground squirrels". Cell Cycle. 11 (9): 1714–1726. doi:10.4161/cc.19799. ISSN 1538-4101. PMID 22510572.
- Thirteen-lined Ground Squirrel Genome Project page at GenBank
- If you know what a 'squinny' is, you're probably from Des Moines
- "Spermophilus tridecemlineatus". Integrated Taxonomic Information System. Retrieved 5 November 2010.
- View the squirrel genome in Ensembl
- View the speTri2 genome assembly in the UCSC Genome Browser.