Field Guide/Mammals/Thirteen-lined Ground Squirrel

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Spermophilus tridecemlineatus (Thirteen Lined Ground Squirrel)
Family: Sciuridae
Size: Weighing around 8 oz (227 g), they are a smaller, more slender squirrel with a body length around 10 inches (25 cm) along with a 3 inch tail (8 cm). [1]
Description: Known for having small ears, elongated bodies, and thirteen stripes down their back from the nape of the neck extending down through the tail. These stripes alternate from a dark brown or black color to a light tan or white and also turn into spots along their back. Their front paws only have four toes with very long claws but the back feet have five toes with normal claws. Their long claws are used for digging along with large cheeks to carry food. [1]
Similar Species: Similar species to the thirteen lined ground squirrel are the Richardson’s Ground Squirrel and the Wyoming Ground Squirrel. They can be differentiated by their small ears, long bodies, and the thirteen strips along their backs. [1]

Range: Home to central North America, it has extended its range over the past two centuries northward and eastward. Currently, they spread from east of Ohio to west of Montana and Arizona. [1]
Habitat: Because they enjoy burrowing, open areas with short grass and well drained soil are common areas to live. Although it used to be mostly prairies, cemeteries, golf courses, and other well groomed areas are now considered home for these gophers. [1]
Diet: Being omnivorous, 50% of the food eaten are animal matter such as insects, bugs, mice, birds, and other small animals. Also, they consume seeds from weeds and available crop species. It will also eat grass, leaves and clovers, flowers, vegetables, fruits, and roots. These animals hardly ever drink water or other liquids and depend on the food that they eat to contain water for hydration. [1] [2]
Activity: These ground squirrels come up when the sun is up and the earth is warm but return to their burrows before sundown. Coming out of their burrow is rare unless the sun is out. They like the warmth of their burrow when it is overcast and rainy. When they first come out of the burrow, you will often see the ground squirrel stand on its hind legs to survey the ground around them to check for predators. These animals begin hibernation anywhere from September to late October depending on their region and come up anytime in late January to March. Males usually begin and end hibernation earlier than females do. [1]

Reproduction: Within two weeks after hibernation, the Thirteen Lined Ground Squirrel begins breeding. On average, only one litter per female is born per year. Averaging around eight to ten babies per liter, they are born hairless and blind with a gestation period of around 28 days. After these 28 days are over, the animal is ready to start weaning off of their mother and start living on their own. Sexual maturity for both males and females is around nine months after birth. [1]
Lifespan: : An estimated 90% of newborn ground squirrels are killed by predators. If the squirrel is fortunate enough to survive it usually only lives around two years. [1]

Notes: The thirteen lined ground squirrels are not colonizing animals and there are only 1 to 20 of these animals per acre but this changes per season. Also, these animals hibernate and allow their heart rates to drop from their normal 200 beats per minute to around 20 beats per minute keeping their body temperatures just slightly above freezing. Not only do they let their heart rates drop during hibernation but they also lose almost 1/3 of their body weight during this time. These little animals also have a great sense of vision, touch, and smell. They use these sounds and secretions to communicate. Also, this species greet each other by touching noses and lips. [1]
Spermophilus tridecemlineatus.jpg

  1. a b c d e f g h i j Petrella, S. (1999), Spermophilus Tridecemlineatus, http://animaldiversity.ummz.umich.edu/accounts/Spermophilus_tridecemlineatus/, retrieved October 5, 2012 
  2. Dolbeer, R. (2005), Thirteen Lined Ground Squirrel and Thier Control, http://icwdm.org/handbook/rodents/13linedgroundsquirrel.asp, retrieved October 5, 2012