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Sciurus vulgarisEurasian red squirrel

By Joshua Seinfeld

Geographic Range

Sciurus vulgaris, also known as the Eurasian red squirrel, can be found throughout the forests of Europe and northern Asia. Over the past century S. vulgaris population densities have changed greatly. The species has remained very common in central Europe, but on Great Britain they are now extirpated from much of their range. (Nowak 1991, Parker 1990)

Habitat

Sciurus vulgaris lives and nests in deciduous and coniferous forests. These squirrels prefer to live in large, mature trees that can provide them with an abundant supply of food in the form of seeds or acorns. Trees chosen as nesting sites usually have hollowed out cavities or large holes in their trunks which can be used as nests. A high quality nest may be used for several years, and individuals always maintain several nests to which they can escape when being pursued by a predator. (Nowak 1991, Parker 1990)

Physical Description

This species has more variation in coat color than almost any other mammal in the Palearctic region. The color of these squirrels varies from light-red to black on their heads and backs. All individuals (except those that are completely melanistic), have white or creamy fur on their stomachs. Like many other tree squirrels, S. vulgaris has long tufts of hair on its ears and long furry tail. In most areas where they are common, such as central Europe, the pelage coloration of individuals varies from red to black, with individuals of many differently color morphs co-occurring. However, in some areas, whole populations may have almost identically colored coats. Examples of populations in which all of the squirrels share the same coat color can be found in Great Britain, where only red members of this species live; and in the Sila region of southern Italy, where only black individuals are found. The body hair of these squirrels changes twice annually, while the tail hair changes only once. The winter coat covers more of the soles of the feet, has longer ear tufts, and is thicker than the spring/summer coat.

Shedding and growth of hair can be delayed or prevented by a lack of food, diseases, or parasitic infestation during the spring or late fall when individuals normally grow a new coat.

The size of the skull also varies between regions. Average skull size in S. vulgaris populations increases from north to south throughout Eurasia.

(Nowak 1991, Parker 1990)

  • Sexual Dimorphism
  • sexes alike
  • Average mass
    600 g
    21.15 oz
    AnAge

Reproduction

When a female comes into estrous, the usually non-gregarious males gather in her home range to compete for the opportunity to mate with her. After mating occurs, male squirrels return to their home ranges.

Female Eurasian red squirrels give birth to an average of two litters per year, of usually 5-7 young. The gestation period is 38-39 days. The young weigh 8-12 g at birth and are born hairless and blind. Their auditory canals are unopened, and their ears are undeveloped and lay flat against their head. The young squirrels' eyes open after 30 days, at which time they become active cleaning themselves and moving around the nest. After 45 days the young voluntarily leave the nest for the first time. At this point the young also begin to eat solid food. By eight to ten weeks of age the offspring are fully weaned and independent, even though they tend to remain near their mothers for some time. Young become reproductively mature within a year. (Macdonald 1984, Nowak 1991, Parker 1990)

  • Breeding interval
    These squirrels reproduce twice during the warm season, at approximately 13 week intervals
  • Breeding season
    Eurasian red squirrels generally have two litters per year, one in February to March, the other from May to August
  • Range number of offspring
    1 to 10
  • Average number of offspring
    3 to 7
  • Average number of offspring
    5
    AnAge
  • Range gestation period
    38 to 39 days
  • Range time to independence
    8 to 10 weeks
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    296 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    1 years
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    320 days
    AnAge

Eurasian red squirrels are cared for and nursed by their mother in her nest during the first few months of their lives.

  • Parental Investment
  • no parental involvement
  • altricial
  • pre-hatching/birth
    • provisioning
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • protecting
      • female

Lifespan/Longevity

The mortality rate of young Eurasian red squirrels is high, due to heavy predation by birds and mammals. Less than one in four survive to their first birthday. Although adults can live for 6 to 7 years in the wild, and longer in captivity, most individuals probably only live for 2-4 years.

Behavior

The daily activities of these squirrels center around obtaining food. They are normally most active in the morning and late afternoon when they consume the most food. During spring and summer, they rest in their nests during the mid-day hours to avoid the extreme heat. During the winter, however, the mid-day rest may be very short or skipped entirely. While these squirrels spend most of their time in the trees, they do come to the ground when necessary to search for food or to bury food items such as acorns and nuts. While Eurasian red squirrels do not hibernate, they do stay in their nests and rest when there are bad storms or strong winds that would make traveling amongst the tree branches dangerous, emerging only when they have to find food. Females also stay in their nest for extended periods of time to care for their young.

Sciurus vulgaris and other tree squirrels are not found in groups, except when males gather within a female's home range to compete for the opportunity to mate with her. They are not territorial and the home ranges of individuals may overlap considerably.

(Nowak 1991, Parker 1990, Tonkin 1983)

Communication and Perception

Eurasian red squirrels have keen senses of vision, smell, touch, and hearing. They communicate with body signals, sounds, such as warning calls, and chemical cues. Within family groups touch is also used in communication.

Food Habits

Sciurus vulgaris regularly forage on coniferous seeds, beechnuts, acorns, and nuts. They have a specialized technique for opening nuts that utilizes the power of the lower incisors. With practice they are able to open a nut in just a few seconds. The dietary habits of these squirrels varies greatly according to the region in which they live and with the availability of different foods. When their regular dietary staples are not available, these squirrels may eat mushrooms and other fungi, birds' eggs, and garden flowers and vegetables. They have also been observed peeling the bark off conifers and licking the trees' sap. Like most squirrels, this species stores food supplies by burying them in the ground or hiding them in the bark of trees. Young squirrels learn what food sources to eat from their mothers. As they get older they become more reluctant to accept new and strange food sources. The daily food intake varies depending upon the time of year. They eat the most food in the spring (80g per day), and the least in the winter (35g per day). (Gromwall et al. 1993, Moiller 1983, Nowak 1991, Parker 1990)

  • Animal Foods
  • eggs
  • Plant Foods
  • leaves
  • seeds, grains, and nuts
  • fruit
  • sap or other plant fluids
  • Other Foods
  • fungus

Predation

Eurasian red squirrels are agile in the trees and are constantly alert for the presence of predators. They are mainly preyed on by large birds of prey and arboreal mustelids like the European marten. As young in the nest they may be taken by large climbing snakes, and other small, arboreal predators.

Ecosystem Roles

Eurasian red squirrels have an important impact on forest communities through seed predation and caching of tree seeds. Forgotten caches may end up sprouting and growing into new trees.

Economic Importance for Humans: Positive

In the former Soviet Union some populations of Sciurus vulgaris are hunted for their thick and luxurious winter coats, which have commercial value on the fur market. (Nowak 1991). This species is also probably an important disperser of the seeds of some species of trees.

  • Positive Impacts
  • body parts are source of valuable material

Economic Importance for Humans: Negative

Sciurus vulgaris are known to occasionally eat shoots of food crop plants. They can also be a nuisance when they nest in houses or buildings because they can be quite noisy. (Nowak 1991)

  • Negative Impacts
  • crop pest
  • household pest

Conservation Status

The number of Eurasian red squirrels has dropped dramatically in recent years in some areas. In Great Britain, the introduction of a North American species of tree squirrel, the eastern gray squirrel (Sciurus carolinensis), has led to the disappearance of native Eurasian red squirrels throughout much of the country, while in the former Soviet Union overhunting of some populations for their fur has reduced their numbers. (Nowak 1991, Parker 1990, Wilson et al. 1993)

This species is listed as "Near Threatened" by the IUCN Red List.

Contributors

George Hammond (editor), Animal Diversity Web.

Joshua Seinfeld (author), University of Michigan-Ann Arbor.

Glossary

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

polygynous

having more than one female as a mate at one time

polymorphic

"many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic. Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Gromwall, O. and A. Pehrson. 1993. Nutrient content in fungi as a primary food of the red squirrel (Sciurus vulgaris). Oceologica. 64(2): 230-31.

Macdonald, D. 1984. The Encyclopedia of Mammals. Facts on File Publishing, NY.

Moiller, H. 1983. Foods and foraging behavior of red (Sciurus vulgaris) and gray (Sciurus carolinensis) squirrels. Mammal Review. 13: 81-98.

Nowak, R.M. 1991. Walker's Mammals of the World. Fifth Edition. The Johns Hopkins University Press, Baltimore. Parker, S.P. 1990. Grzimek's Encyclopedia of Mammals, vol. II. McGraw-Hill Publishing Co. NY.

Tonkin, J.M. 1983. Activity patterns of the red squirrel (Sciurus vulgaris). Mammal Review. 13: 99-111.

Wilson, E.D., and D.M. Reeder. 1993. Mammal Species of the World: a Taxonomical and geographical reference. Smithsonian Institution Press, Washington.

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