Richardson's Ground Squirrel
Encyclopedia
Richardson's ground squirrel (Urocitellus richardsonii), or the flickertail, is a North America
n ground squirrel
in the genus Urocitellus
. Like a number of other ground squirrels, they are sometimes called "Dak Rats" or "gophers", though this name belongs more strictly to the pocket gopher
s of family Geomyidae.
naturalist Sir John Richardson
. The Gopher Hole Museum in Torrington, Alberta, Canada, has a large selection of stuffed ground squirrels of many varieties and colors. North Dakota
is nicknamed the Flickertail state after the squirrel.
s, Richardson's ground squirrel is found mainly in the northern states of the United States
, such as North Dakota
, and in southern Canada
, such as southern Alberta
and southern Saskatchewan
. The range of this animal expanded as forests were cleared to create farm land. They are not simply restricted to prairie; sometimes adapting to suburban environments, causing them to be seen as pests because of the burrows they dig. It is not unusual to find squirrels digging tunnels under the sidewalks and patios of urban homes.
the squirrels weigh between 200 and 400 grams, but by the time they hibernate again this may have risen to nearly 750 g. 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".
Richardson's ground squirrels appear to live communally, but they organize their social structure around female kinship. A female Richardson's ground squirrel will tolerate the presence of closely related females, but are territorial towards other individuals. Individuals are territorial around their nest sites, the burrows of Richardson's ground squirrels are grouped closely together in colonies, and individuals give audible alarm call
s 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. Offspring genetically have calls that resemble those of their parents so the adults can pick up on their own offspring's call when danger threatens.
Predators include hawk
s, weasels, badger
s and coyote
s.
before the females emerge a couple of weeks later. Abandoned burrows are sometimes taken over by other grassland species such as the burrowing owl
.
Because they will readily eat crop species, Richardson's ground squirrels are sometimes considered to be agricultural pest
s, although this is not their legal status in all jurisdictions. The government of Saskatchewan declared the animals pests in 2010, allowing local governments to employ gopher control measures.
The Saskatchewan Wildlife Federation sponsored a 12-week "gopher derby" in 2002, in an effort to reduce what it considered an overpopulation of the squirrels. Cash prizes were awarded for the most number of animals killed, with the animals' tails being presented as proof of the kill. The Canadian Humane Society called the contest cruel and barbaric. Despite the criticism, the derby was repeated in 2003. By 2004, the gopher population had dropped and the contest was cancelled.
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n ground squirrel
Ground squirrel
The ground squirrels are members of the squirrel family of rodents which generally live on or in the ground, rather than trees. The term is most often used for the medium-sized ground squirrels, as the larger ones are more commonly known as marmots or prairie dogs, while the smaller and less...
in the genus Urocitellus
Urocitellus
Urocitellus is a genus of ground squirrels. They were previously believed to belong to the much larger genus Spermophilus, but DNA sequencing of the cytochrome b gene showed that this group was paraphyletic to the prairie dogs and marmots,, and could therefore no longer be retained as a single genus...
. Like a number of other ground squirrels, they are sometimes called "Dak Rats" or "gophers", though this name belongs more strictly to the pocket gopher
Pocket gopher
The pocket gophers are burrowing rodents of the family Geomyidae. These are the "true" gophers, though several ground squirrels of the family Sciuridae are often called gophers as well...
s of family Geomyidae.
Name
This squirrel was named after the ScottishScotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
naturalist Sir John Richardson
John Richardson (naturalist)
Sir John Richardson was a Scottish naval surgeon, naturalist and arctic explorer.Richardson was born at Dumfries. He studied medicine at Edinburgh University, and became a surgeon in the navy in 1807. He traveled with John Franklin in search of the Northwest Passage on the Coppermine Expedition of...
. The Gopher Hole Museum in Torrington, Alberta, Canada, has a large selection of stuffed ground squirrels of many varieties and colors. North Dakota
North Dakota
North Dakota is a state located in the Midwestern region of the United States of America, along the Canadian border. The state is bordered by Canada to the north, Minnesota to the east, South Dakota to the south and Montana to the west. North Dakota is the 19th-largest state by area in the U.S....
is nicknamed the Flickertail state after the squirrel.
Habitat
Native to the short grass prairiePrairie
Prairies are considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type...
s, Richardson's ground squirrel is found mainly in the northern states of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, such as North Dakota
North Dakota
North Dakota is a state located in the Midwestern region of the United States of America, along the Canadian border. The state is bordered by Canada to the north, Minnesota to the east, South Dakota to the south and Montana to the west. North Dakota is the 19th-largest state by area in the U.S....
, and in southern Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, such as southern Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
and southern Saskatchewan
Saskatchewan
Saskatchewan is a prairie province in Canada, which has an area of . Saskatchewan is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, and on the south by the U.S. states of Montana and North Dakota....
. The range of this animal expanded as forests were cleared to create farm land. They are not simply restricted to prairie; sometimes adapting to suburban environments, causing them to be seen as pests because of the burrows they dig. It is not unusual to find squirrels digging tunnels under the sidewalks and patios of urban homes.
Description
Typical adults are about 30 cm long. Weights vary greatly with time of year and with location: at emergence from hibernationHibernation
Hibernation is a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate. Hibernating animals conserve food, especially during winter when food supplies are limited, tapping energy reserves, body fat, at a slow rate...
the squirrels weigh between 200 and 400 grams, but by the time they hibernate again this may have risen to nearly 750 g. 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
Prairie dog
Prairie dogs are burrowing rodents native to the grasslands of North America. There are five different species of prairie dogs: black-tailed, white-tailed, Gunnison's, Utah and Mexican prairie dogs. They are a type of ground squirrel, found in the United States, Canada and Mexico...
than a typical ground squirrel. The tail is constantly trembling, so the animal is sometimes called the "flickertail".
Behavior
Alarm call
In the field of animal communication, an alarm signal is an antipredator adaptation referring to various signals emitted by social animals in response to danger. Many primates and birds have elaborate alarm calls for warning conspecifics of approaching predators. For example, the characteristic...
s when possible predators approach. Recent research has shown that in some cases, ultrasonic
Ultrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
alarm calls are given, and are responded to by other members of the colony. Offspring genetically have calls that resemble those of their parents so the adults can pick up on their own offspring's call when danger threatens.
Predators include hawk
Accipitridae
The Accipitridae, one of the two major families within the order Accipitriformes , are a family of small to large birds with strongly hooked bills and variable morphology based on diet. They feed on a range of prey items from insects to medium-sized mammals, with a number feeding on carrion and a...
s, weasels, badger
American Badger
The American badger is a North American badger, somewhat similar in appearance to the European badger. It is found in the western and central United States, northern Mexico and central Canada, as well as in certain areas of southwestern British Columbia.Their habitat is typified by open...
s and coyote
Coyote
The coyote , also known as the American jackal or the prairie wolf, is a species of canine found throughout North and Central America, ranging from Panama in the south, north through Mexico, the United States and Canada...
s.
Hibernation
Adult ground squirrels may hibernate as early as July, though in their first year, the young ground squirrels do not hibernate until September. The males emerge from hibernation in March, and establish territoriesTerritory (animal)
In ethology the term territory refers to any sociographical area that an animal of a particular species consistently defends against conspecifics...
before the females emerge a couple of weeks later. Abandoned burrows are sometimes taken over by other grassland species such as the burrowing owl
Burrowing Owl
The Burrowing Owl is a tiny but long-legged owl found throughout open landscapes of North and South America. Burrowing Owls can be found in grasslands, rangelands, agricultural areas, deserts, or any other open dry area with low vegetation. They nest and roost in burrows, such as those excavated...
.
Reproduction
Female Richardson's ground squirrels produce one litter per year. The young, up to 8 in a litter, are born in April or May. Young ground squirrels remain underground in the burrow until they are approximately 30 days old.Relationship with humans
Pest (animal)
A pest is an animal which is detrimental to humans or human concerns. It is a loosely defined term, often overlapping with the related terms vermin, weeds, parasites and pathogens...
s, although this is not their legal status in all jurisdictions. The government of Saskatchewan declared the animals pests in 2010, allowing local governments to employ gopher control measures.
Control measures
Farmers and ranchers have developed a variety of ways to exterminate gophers besides trapping, shooting and poisoning. One such process fills the burrows with a mixture of oxygen and propane and then ignites the gas mixture. This kills the gophers with a concussive force that also collapses the tunnel systems. While both solutions are effective, gophers from outside of the treated areas will eventually spread back into the area.The Saskatchewan Wildlife Federation sponsored a 12-week "gopher derby" in 2002, in an effort to reduce what it considered an overpopulation of the squirrels. Cash prizes were awarded for the most number of animals killed, with the animals' tails being presented as proof of the kill. The Canadian Humane Society called the contest cruel and barbaric. Despite the criticism, the derby was repeated in 2003. By 2004, the gopher population had dropped and the contest was cancelled.
Pet trade
The Richardson's ground squirrel in recent years has become popular in the exotic pet trade.External links
- Xander.it - Spermophilus richardsonii (Richardson's ground squirrels) videos
- American Society of Mammalogists species account (pdf)
- Information on keeping Richardson's ground squirrels as pets
- Dr. Gail Michener's site on Richardson's ground squirrel