Status and Importance
Ground squirrels play an important role in the ecology of Alberta's wildlife. Ground squirrels are a major source of food for many predatory birds, mammals and reptiles. One species of raptor, the ferruginous hawk, depends almost entirely on ground squirrels to fledge their chicks. Similarly, many other species rely on ground squirrels as a major food source.
The population status of Richardson's ground squirrels varies from year to year but is generally rated as "not at risk." Richardson's ground squirrels are also unregulated, which means they can be lawfully shot, trapped or otherwise removed where permitted.

Life History
The Richardson's ground squirrel is a burrowing rodent found throughout most of the prairie and parkland regions of Alberta (Figure 1). It is the most common ground squirrel of the five species found in Alberta. The other species are Franklin's (bush gopher), Columbian, thirteen-lined and golden-mantled. The Richardson's ground squirrels are the most prevalent colony dwellers of the five species.

Richardson's ground squirrels spend the majority of their life underground. In their underground burrow system, they usually mate, raise their litters for the first 28 days, avoid predators (except weasels and badgers) and inclement weather (heat, cold and rain). They sleep underground from just before sunset until shortly after sunrise and hibernate for up to eight months in their burrows.

Each adult female owns at least one burrow system that has five to seven exits and two to five sleeping chambers, one of which is used for rearing young. Vacated burrow systems are soon taken over by dispersing Richardson's ground squirrels. Occasionally badgers, burrowing owls, foxes or coyotes may use ground squirrel burrows.

Reproduction
Both males and females are reproductively mature the year following their birth. Mating occurs only in spring, shortly after females emerge from hibernation. A female that fails to become pregnant or loses her embryos or infants is incapable of breeding again until the following year.
Females are fertile for only two to three hours on one afternoon on one day each year and will mate with several males during that time. Males also copulate with several females. Only one litter per female is produced each spring.
A litter of 6 to 8, with an equal number of males and females, is born underground after a 23-day gestation. At birth, the infants are naked, blind, helpless and totally dependent on their mother. At first emergence aboveground, when four weeks old, juveniles immediately begin eating solid food and rapidly become nutritionally independent of their mother.

Litter size often varies with the quality of vegetation available, averaging between five to six young on native pasture and expanding up to nine or ten on tame forage crops.
During June and July, most of the young ground squirrels seek new areas to establish colonies as far as 3 km away. Ground squirrels vigorously defend their burrows and foraging area from other ground squirrels.

Life Span
Natural mortality among Richardson's ground squirrels is quite high, particularly in males. As a result, the sex ratio among adults is about four females for each male. Females live about four years (maximum six), on average, while males usually live only one year (maximum two to three).
The major cause of death is predation and starvation; only half the females and less than one fifth of the males born each year will reach adulthood.

Hibernation
Richardson's ground squirrels have evolved to escape the prolonged winter period by hibernating, a torpor-like state in which the body temperature drops while heart and respiration rates slow down dramatically.
To survive without food or water for periods exceeding 210 days, ground squirrels need to consume vast amounts of food high in energy to develop a reservoir of body fat. Adult males enter hibernation sometime in late July, females several weeks later followed by juveniles until freeze-up.
Each animal hibernates alone in a special chamber (called the hibernaculum) that it prepares up to four to six weeks in advance, but does not use until ready to hibernate. The hibernaculum is sealed off with a soil plug. The only predator capable of getting into the hibernaculum is the badger.
Males emerge from hibernation from late February to mid-March while females come out about two weeks later.

Social Behavior
Richardson's ground squirrels live in groups of closely related female kin. Females live their entire life in or near their birth site, but males of the year tend to disperse and leave their birth area after weaning.
As soon as the female is pregnant, she will not tolerate males, including her mate(s). Females will only tolerate their female relatives (i.e., mother, grandmother, daughters, etc.) and are aggressive to all other squirrels. Females recognize their kin throughout life, even after many months without contact during hibernation.
Each female rears her litter by herself with no assistance from male or female relatives. Males do not form any social associations, either with other males or with females.

Diet
Richardson's ground squirrels eat a wide variety of food. Most prefer succulent green vegetation such as grasses, forbs, young shrubs and seeds. Richardson's ground squirrels occasionally eat insects and scavenge road-killed ground squirrels, but they very rarely kill for food.
Little is known about the preferred natural diet of Richardson's ground squirrels, but the assumption is the relatively high nutrient and oil content of seeds helps in the deposition of fat necessary for hibernation. Richardson's ground squirrels are also known to store large quantities of food in burrows. Males store seed in the hibernating chamber while females do not store seeds.

Weight
The body weight of Richardson's ground squirrels increases dramatically through the spring and summer months and can double during this period. Adult males weigh about 500 gm (1 lb.) by fall and females about 350 gm (3/4 lb).

Ground Squirrel Damage
Damage caused by Richardson's ground squirrels ranges from an occasional headache for some to a significant loss of crop production to others.
The most common types of ground squirrel damage are crop loss through direct consumption and reduced production due to plant injury and trampling. In addition, downtime and repair costs due to damage to hay binds as well as physical injury to livestock with ground squirrel burrows and those of badgers are also major concerns.
Burrowing activity in green spaces such as ball diamonds, golf courses and cemeteries as well as the risk of an air strike because of large birds attracted by ground squirrels at airports are serious problems for urban managers.
Despite decades of conflicts with ground squirrels, the extent, causes and magnitude of ground squirrel damage have never been fully investigated. This information shortfall has greatly impeded the development of effective, long term control measures.
An in-depth analysis of the causative and associated dynamics of ground squirrel damage as well as a thorough understanding of the biology and behaviour of the animal are vital for the development of a sustainable, long term, affordable and appropriate management strategy.