Richardson's Ground Squirrel
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| Richardson's Ground Squirrel Conservation status: Lower risk (lc) | ||||||||||||||||
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| Spermophilus richardsonii (Sabine, 1822) |
Richardson's Ground Squirrel (Spermophilus richardsonii) is a North American ground squirrel in the genus Spermophilus. Like a number of other ground squirrels, they are sometimes called "gophers", though this name belongs more strictly to the pocket gophers of family Geomyidae.
Native to the short grass prairies, Richardson's Ground Squirrel is found mainly in the northern states of the United States and in southern Canada, such as North Dakota and southern Alberta. The range of this animal expanded as forests were cleared to create farm land.
Typical adults are about 30cm long. Weights vary greatly with time of year and with location: at emergence from hibernation the squirrels weigh between 200 and 400 grams, but by the time they hibernate again this may have risen to nearly 750 grams; males are slightly larger and heavier than females on average. They are dark brown on the upper side and tan underneath. The tail is shorter and less bushy than in other ground squirrels, and the external ears are so short as to look more like holes in the animal's head. Behavior is more like that of a prairie dog than a typical ground squirrel. The tail is constantly trembling, so the animal is sometimes called the "Flickertail".
Although they are territorial around their nest sites, the burrows of Richardson's ground squirrels are grouped closely together in colonies, and individuals give audible alarm calls when possible predators approach. Recent research has shown that in some cases, ultrasonic alarm calls are given, and are responded to by other members of the colony.
Richardson's Ground Squirrels hibernate; adult squirrels may hibernate as early as July, though in their first year, the young squirrels do not hibernate until September. The males emerge from hibernation in March, and establish territories before the females emerge a couple of weeks later. The young, up to 8 in a litter, are born in April or May. Abandoned burrows are sometimes taken over by other grassland species such as the burrowing owl.
These animals are omnivores, eating seeds, nuts, grains, grasses and insects. Predators include hawks, weasels, badgers and coyotes. Because they will readily eat crop species, Richardson's Ground Squirrels are sometimes considered to be agricultural pests. Farmers and ranchers have developed some ingenious ways of exterminating the gopher from their land in addition to normal shooting and poisoning. One enterprising farmer recently used a large sewage vacuum truck with which he sucked the beasts up out of their dens and into the tank. Another, more unfeeling person, used propane. He built a propane supply pipe with an electical sparker at the end. He would poke the pipe into a hole, exhaust some propane into the den and then hit the spark, with the expected results. In the end, the procreative drives in the gophers always win out.
This animal was named after the Scottish naturalist Sir John Richardson. The Gopher Museum in Torrington, Alberta, Canada, has a large selection of stuffed ground squirrels of many varieties and colors.
External links
- American Society of Mammalogists species account (http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/pdf/i0076-3519-243-01-0001.pdf)
- Information on keeping Richardson's Ground Squirrels as pets (http://centralpets.com/pages/critterpages/mammals/rodents/ROD4274.shtml)
- Ultrasonic Squirrel a Mammalian First (http://dsc.discovery.com/news/afp/20040726/squirrel.html)