Richardson's Ground Squirrels

Frequently Asked Questions About Richardson's Ground Squirrels
(also known as gophers)

 

For more detailed information than given in the answers below, use the links and drop-down menus across the top of this page

 

Are Richardson's ground squirrels really squirrels?
Yes, they really are squirrels. Richardson's ground squirrels are one of 21 species of ground squirrels found in North America, all of which live in and on the ground. Many people think squirrels must have big bushy tails, but only squirrels that live in trees need a large tail for balance. For further information, see Related Species.

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Why do many people refer to Richardson's ground squirrels as gophers?
The word gopher derives from the French gaufre, referring to something that appears honeycombed by holes. Many animals that use tunnels in the ground are called gophers, including the gopher snake (Pituophis catenifer), gopher tortoise (Gopherus polyphemus), gopher frog (Rana capito), and pocket gophers (rodents in the genera Geomys and Thomomys). People from Europe and eastern North America were familiar with tree squirrels, but when they came to the prairies and saw mammals without bushy tails going in and out of burrows, the settlers did not realize they were looking at a true, but ground-dwelling, squirrel. Although the name spermophile (derived from the genus name Spermophilus) was in use, it never became part of the everyday language. Instead, frontiers-people adopted the name gopher, already commonly used for other species of ground squirrels living in various part of the USA. Consequently, many different species of ground squirrels throughout North America are called gophers, which further adds to the confusion.

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Are Richardson's ground squirrels native to North America?
Yes, Richardson's ground squirrels evolved on the prairies of North America many thousands of years ago. The first specimens to be obtained by European scientists were collected by British explorers when they mapped the Saskatchewan River in 1820. For further information, see Species Description.

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Are Richardson's ground squirrels the same as prairie dogs?
No; although they are close relatives of prairie dogs, Richardson's ground squirrels are a separate species. Superficially, Richardson's ground squirrels (Urocitellus richardsonii) look like black-tailed prairie dogs (Cynomys ludovicianus), but black-tailed prairie dogs are larger and have a shorter tail with a conspicuous black tip. Richardson's ground squirrels and black-tailed prairie dogs overlap geographically in areas such as southern Saskatchewan and Montana. For further information, see Similar Species.

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Why are they called Richardson's ground squirrels?
Richardson's ground squirrels are named in honour of Sir John Richardson, the surgeon-naturalist on two British naval expeditions charged with mapping the arctic coast of British North America (now Canada). During the over-land part of the expedition, John Richardson explored along the Saskatchewan River to Fort Carlton, where he collected specimens of a new rodent species in May 1820. He sent these specimens back to England, where they were named in 1822 by Joseph Sabine of the Linnean Society and given the specific epithet richardsonii. For further information, see Species Description.

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What is the scientific name of Richardson's ground squirrels?
The original scientific name given to the Richardson's ground squirrel by Jospeh Sabine in 1822 was Arctomys richardsonii.  In the 1800s the science of taxonomy was in its early stages and methods of communication were very slow, which resulted in two scientists independently renaming Richardson's ground squirrels as Citellus richardsonii and Spermophilus richardsonii with the latter becoming the accepted scientific name until 2009 when a major taxonomic revision of the genus Spermophilus resulted in reclassification of all the North American ground squirrels into six other genera (Helgen at al. 2009, Journal of Mammalogy vol. 90 pp. 270-305).  Richardson's ground squirrels are now placed in the genus Urocitellus; their specific epithet is unchanged, so the Latinized scientific name is now Urocitellus richardsonii.  

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What do Richardson's ground squirrels eat?
Richardson's ground squirrels are predominantly herbivores, eating various plants and seeds. They sometimes eat insects such as grasshoppers, and they occasionally eat easily obtainable meat (such as roadkill) and damaged eggs. For further information, see Diet.

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Do Richardson's ground squirrels drink water?
Only rarely in the wild.  Free-living Richardson's ground squirrels usually do not have access to water, but they will drink if water is readily available. Because Richardson's ground squirrels live on the dry prairie, many of them only ever have access to water after a spring snowstorm, summer rain, or on a dewy morning. To stay in water balance in the absence of a source of drinking water, ground squirrels reduce water loss from the body by producing dry feces, by making small amounts of concentrated urine, by retreating underground in the heat of the day, and by spending large amounts of time curled up in a cool, moist nest located deep underground. By minimizing water loss, Richardson's ground squirrels are able to meet their water needs from the limited amount of water in the food they eat

Because room air is usually too dry for them to maintain water balance, captive ground squirrels MUST be provided with a water bottle for drinking.  However, they prefer to obtain water from foods such as lettuce or water melon that have a high water content.

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When do Richardson's ground squirrels hibernate?
Overall, Richardson's ground squirrels spend over half their life in hibernation, and the timing and duration of hibernation vary with age and sex.  Adult Richardson's ground squirrels are active for about 110 days and hibernate for the remaining 255 days of the year.  Exact dates vary slightly from year to year and across the geographic range of the species.  In southern Alberta, adult males are active from mid-February through mid-June; most adult males are already back in hibernation before the summer solstice.  Adult females come out of hibernation about 2 weeks after males and go back into hibernation in early July.  From mid-July onwards, the only Richardson's ground squirrels active aboveground are juveniles born that spring.  Juveniles females hibernate from mid-August to early March, and juvenile males hibernate from October to mid-February.  Thus, although Richardson's ground squirrels can be seen above ground from February through October, no individual animal is ever active for more than a few months of the year.  For further information, see Annual Activity Cycle.

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How long do Richardson's ground squirrels live?
In nature, mortality in the first year of life is high, so the majority of individuals never survive to adulthood and reproductive age. Furthermore, although males and females are born in about equal numbers, fewer males than females survive each year of life. Typically only 5-15% of young males and 35-45% of young females survive to adulthood. Thereafter, about 25% of adult males and 50% of adult females survive for another year.

Free-living adult males in nature experience high mortality associated with the mating season and rarely live to the age of 3 years.  Some female Richardson's ground squirrels live to 3 or 4 years of age and, occasionally, a year or two longer. The maximum confirmed lifespan in nature is 7 years for a female and 4 years for a male.  Males can live longer in captivity.  As pets living in a safe environment with abundant food and limited exercise, both female and male Richardson's ground squirrels often live for 3-5 years, and occasionally 6-7 years. For further information, see Survival & Longevity.

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What are the major predators of Richardson's ground squirrels?
Many predators favour eating Richardson's ground squirrels. The most significant ones are North American badgers (Taxidea taxus), long-tailed weasels (Mustela frenata), and Swainson's hawks (Buteo swainsoni). Some other predators are coyotes (Canis latrans), red-tailed hawks (Buteo jamaicensis), and prairie rattlesnakes (Crotalus viridis). For further information, see Predators & Parasites.

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How many offspring do Richardson's ground squirrels produce?
Richardson's ground squirrels are not sexually mature until after their first hibernation season, by which time they are nearly one year old. Each female can produce only one litter a year; if the litter is aborted during pregnancy or lost to predation during lactation, the mother cannot produce another litter until the subsequent year. About 75% of litters have 5, 6, 7, or 8 offspring. Under natural circumstances, over half of those offspring will fail to survive their first year of life. For further information, see Reproduction.

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Do Richardson's ground squirrels mate for life?
No; the association between a male and a female lasts only an hour or so, just long enough for courtship and copulation. In fact, female Richardson's ground squirrels sometimes mate with 2 or 3 males during the one afternoon that they are in estrus in the early spring. A female Richardson's ground squirrel does not allow any males into the burrow system in which she gives birth and raises her litter. Males never assist with rearing young, and males probably never know which are their own young. Because males have a shorter life span than females, females almost always mate with different males in different years. For further information, see Reproduction & Development, Reproductive Behavior, and Sexual Differences in Behavior.

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When do Richardson’s ground squirrels mate?
The mating season is restricted to a period of 2-3 weeks in very early spring.  Each female is receptive to males on only one day, after which she will not mate again until the following year.  Each male produces sperm for about 4 weeks, after which his testes regress and return into the abdominal cavity until the following year.  Behaviours that are sometimes mistaken for mating during the summer are actually juveniles play mounting each other. For further information, see Reproductive Behavior and Sexual Differences in Behavior.

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How can the sex of a Richardson's ground squirrels be determined?
Although male Richardson's ground squirrels are larger than females, the difference in size is hard to distinguish from a distance. The most reliable way to sex a ground squirrel is by looking at the ano-genital distance, but this requires having the animal in hand. The ano-genital distance is longer in males than in females, with the scrotal skin of the male accounting for the additional distance between the anus and the urinary opening. Because the testes descend into the scrotum for only about 4 weeks a year (see Reproduction), most of the time there is no conspicuous bulge in the scrotal area of males. During the mating season, when males engage in fights that result in severe wounds, males can often be distinguished from a distance by their tattered and torn appearance.

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How deep are the tunnels in a Richardson's ground squirrel burrow system?
The burrow system can go as deep at 1 metre (100 cm), but most parts of the system are between 25 and 75 cm deep. The deepest part of a burrow system is a drain tunnel that diverts water away from sleeping and hibernation chambers.  Chambers can be located as deep at 80 cm, but the average depth at which a Richardson's ground squirrel hibernates is 50-60 cm. For further information, see Burrow System.

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How many entrances are there to a Richardson's ground squirrel burrow system?
The number of entrances into a burrow system depends on the age of the system. Burrowing begins with the construction of a blind-ending bolt hole with a single opening. Later this is extending into a simple U-shaped tunnel with two openings. By the time a system has been in use for a few months, it has at least 3 or 4 entrances. Well-used burrow systems that have been in use for years have at least 5 to 10 entrances, with many metres of underground tunnels interconnecting the various entrances. For further information, see Burrow System.

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Are Richardson's ground squirrels dangerous?
As with other wild animals, Richardson's ground squirrels are likely to bite when they are scared or handled improperly. Free-living wild animals should only be captured and handled by a qualified experienced person. Richardson's ground squirrels can be tamed, though usually only if they were born in captivity. Although Richardson's ground squirrels have the potential to be vectors of diseases transmissible to humans, no examples of transmission have been reported in the past 60 years. Furthermore, of several thousand fleas collected from Richardson's ground squirrels in a 3-year study in Saskatchewan, none carried disease-producing organisms.

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Can I keep a Richardson's ground squirrel as a pet?
Richardson's ground squirrels can potentially make good pets, but they often revert to wild type behaviour as they age.  It is best to acquire a young squirrel that was born in captivity, rather than captured from the wild, and it is necessary to socialize them by frequent handling.  Richardson's ground squirrels sell for large amounts of money outside their natural geographic range of northwestern North America.  However, they rarely survive more than 3-5 years.  For further information, see Richardson's ground squirrels as Pets.

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Are all Richardson's ground squirrels the same colour?
Albino (pure white fur, white claws, red eyes) and melanistic (completely black) Richardson's ground squirrels are occasionally produced. These unusual colours are due to recessive genes. The survival rate of these two colour variants in nature is probably very low, due to their increased conspicuousness and, for albinos, poor eyesight. For further information, see Species Description.

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Are Richardson's ground squirrels endangered?
Although Richardson's ground squirrels are absent from some former habitats that have been converted by humans to cities, suburbs, parks, golf courses, and agricultural fields, the species as a whole is not endangered.

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How can I keep Richardson's ground squirrels out of the lawn, garden, and yard?
Once Richardson's ground squirrels have established burrow systems, controlling them becomes difficult because removal of animals results in vacant burrows that are eventually re-occupied by other squirrels. If an area is already inhabited by ground squirrels, those animals first have to be removed humanely. Then the area should be tilled as deep as possible to destroy existing tunnels and entrances.  Because chambers are located at depths of 35-80 cm, very deep tilling is required to destroy those portions of the burrow system.

Before planting the new lawn or garden, spread chicken-wire on the ground, then cover the wire with sod or top soil; this prevents new holes being dug by ground squirrels. If ground squirrels start to invade, take immediate action to make new holes unattractive by filling them with expanding foam, covering with gravel and rocks, or pouring in unpleasant smelling liquids. Ground squirrels can be very persistent at trying to get back into a hole, so often these steps need to be repeated over a week or more until the animal gives up. Richardson's ground squirrels do feel pain, so only humane methods are acceptable for actually capturing and killing the animals.

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What good are Richardson's ground squirrels?
Unlike humans, Richardson's ground squirrels do not commit atrocities such as war, torture, genocide, rape, and terrorism.  Although they do modify their environment by creating underground burrow systems in which to live, humans not ground squirrels are responsible for the conversion of about 80% of the Canadian prairie into urban centres, roads and highways, and agricultural fields.   Richardson's ground squirrels attempt to live peacefully in the habitat in which they evolved and in which they lived in harmony with indigenous peoples.

Richardson's ground squirrels are integral members of the prairie ecosystem. Their burrows create protected habitat for other prairie species such as burrowing owls, salamanders, and bumblebees, and they are a food source for hawks, badgers, and many other carnivores. If Richardson's ground squirrels were exterminated, other species native to the prairie habitat would be affected. For further information, see Habitat & Home Range.

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