Eurasian Red Squirrel
Tagged: animal, bird, cat, insectSciurus vulgaris
Red squirrels are common across Europe, but are rapidly being replaced by American gray squirrels in Britain. Such a fate may also overtake their continental cousins. Only 100 years ago the red squirrel was common and the only squirrel in Britain and across continental Europe. Now it is extinct in southern England, except on three islands off the coast. It is still found in Scotland and remains widespread in northern England, although its numbers there are declining fast. Apart from these areas, it survives in a few scattered localities in Wales and eastern and central England. In its place has come the American gray squirrel, introduced to Britain between 1876 and 1929. The American gray has proved a highly successful invader, becoming the squirrel commonly seen in most British woodlands, parks, and gardens. Many people blame the grays for attacking and driving out the native red squirrel or for passing on fatal diseases. In fact, there is no evidence that it is guilty of either of these crimes, although one natural disease that kills red squirrels does not affect grays. The main problem seems to be that while the European red squirrel is satisfactorily adapted to life in coniferous woodlands, it is simply less well equipped than the gray to survive in deciduous forests. Gray squirrels originated in the hardwood forests of North America and are at home in similar woodland areas of lowland Britain. While the reds can survive in deciduous forests on their own, they are at a disadvantage in such environments when they face competition from the grays. The result is that once the grays spread into an area, the reds disappear within about 15 years. Attempts to reintroduce them back into the areas from which they disappeared have not been successful.
A Question of Adaptation
One major problem is that red squirrels cannot digest acorns properly. Acorns are the main food available in the fall in most lowland forests. Grays thrive on them, and they also compete for hazelnuts, the reds’ favorite food in deciduous woodland. Since gray squirrels normally live at double the population densities of reds, they eat at least twice as many nuts, leaving the latter with insufficient food resources. Eurasian red squirrels feed mainly in the treetops, so they cannot afford to store much fat for the winter without running the risk of becoming clumsy climbers. Grays, on the other hand, forage more on the ground and so can accumulate larger fat reserves because agility in the treetops is less important for them. With less fat to tide them over periods of scarcity, reds have to feed regularly, whatever the weather. Since they do most of their foraging in the trees, they are also limited in the range of food available to them. In contrast, the ground-feeding grays not only have access to a wider selection of forage but can also find enough to meet their needs in a much shorter time, a substantial advantage in spells of bad weather.
Ironically, native red squirrels have simply turned out to be less well adapted to cope with the British weather and living conditions than the invasive grays, and so they have lost out in competition with the newcomers. Sadly, the same story has been repeated in Ireland, where the gray squirrel was first released in 1913; it has now spread through the country, again at the expense of the red. Still more alarmingly, grays are now spreading across northern Italy. The species was introduced there in 1948 and in 1966, near Turin. If they spread, the grays will threaten red squirrels throughout the rest of Europe. Attempts to curb the threat to Eurasian red squirrels by eliminating the grays have been stopped by animal-rights supporters, who have managed to win legal backing for their efforts to halt the killings. The situation raises a difficult moral dilemma. If the few hundred introduced gray squirrels have a right to life, should the threatened red squirrel population not benefit from similar protection? And if so, how can their future be assured in the face of a challenge from outside, except by culling the newcomers?
Data Panel
Eurasian red squirrel (European red squirrel)
Sciurus vulgaris
- Family: Sciuridae
- World population: Probably at least 2 million spread over a huge area
- Distribution: Europe and Asia, from Britain east to China and northern Japan
- Breeding: Usually 3 ( but up to 8 ) young per litter; 1 or sometimes 2 litters per year after a gestation period of 5-6 weeks. Life span up to 7 years in the wild, but many die young; 10 years in captivity
- Habitat: Forest, especially coniferous forest
- Size: Length head/body: 7-10 in (18-24 cm); tail: 5-8 in (14-20 cm). Weight: 9-12 oz (250-350 g)
- Form: Bright chestnut red in summer, darker in winter; large bushy tail and (in winter) prominent ear tufts
- Diet: Pine seeds, nuts, fruit, and fungi; occasionally insects and birds’ eggs
- Related endangered species: Some local populations and subspecies of squirrels and chipmunks in the U.S. are Critically Endangered, Endangered, or Vulnerable, but (as with the Eurasian red squirrel) whole species are not at risk
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