Red Squirrel vs Gray Squirrel: Key Differences in the UK

Key differences at a glance

The red squirrel is the native squirrel of Britain, Europe and northern Asia. The eastern gray squirrel is a North American species that people released in Britain from 1876, and it has since replaced the red across most of England and Wales. The table at the top of this page sums up their differences.

Size and build

The gray squirrel is clearly the bigger animal. An adult gray weighs roughly 1.5–2 times as much as a red, at about 400–600 g (14–21 oz) compared with 250–340 g (9–12 oz). The gray’s head and body measure about 23–30 cm (9–12 in) plus a 19–25 cm (7.5–10 in) tail; the red’s head and body measure about 19–23 cm (7.5–9 in) plus a 15–20 cm (6–8 in) tail.

Grays look chunkier, with a broader head and heavier body. Reds look slighter and more delicate, with a proportionally large, fluffy tail.

Ear tufts: the best clue

Red squirrels grow long tufts of hair on the tips of their ears, at their longest in autumn and winter. In summer, after the molt, the tufts become short or disappear, so a red squirrel in July may have plain rounded ears.

Gray squirrels never have ear tufts. Their ears are small and rounded, often with a pale or white patch of fur on the back in winter. If you see clear tufts, you are almost certainly looking at a red squirrel.

Coat color, and why it can mislead

Most red squirrels in Britain are ginger or chestnut, with a cream or white belly. But the color varies: winter coats can look gray-brown, and in continental Europe and Asia many red squirrels are dark brown or nearly black. A dark red squirrel in Germany or Austria is still a red squirrel.

Gray squirrels are mainly silver-gray, but many have reddish-brown or rusty fur along the back, the flanks, the feet and the face, especially in summer. Some are almost black. So a “red” squirrel in a London park is very likely a gray with a brownish summer coat.

The tail is a useful check. A gray squirrel’s tail has a silvery-white fringe around the edge, like a halo. A red squirrel’s tail is ginger to brown, and in many British reds it bleaches to a pale cream color by late summer.

Diet and feeding

Both species eat mainly seeds, nuts, buds, flowers, fungi and fruit, and both store food for winter. The key difference is acorns. Gray squirrels digest acorns efficiently despite their bitter tannins, while red squirrels gain much less from them. This gives grays a big advantage in oak woods, which are common in lowland Britain.

Red squirrels are skilled at extracting small seeds from conifer cones, which helps them hold their own in large pine and spruce forests. Grays also spend more time foraging on the ground and readily raid gardens and bird feeders. Both bury nuts and seeds one at a time to eat later, but studies suggest gray squirrels remember their hiding places more accurately and for longer than reds do. More on squirrel food is in what do squirrels eat?

Habitat, behavior and life cycle

In Britain today, red squirrels live mainly in large conifer and mixed forests, in Scotland, northern England, Anglesey, the Isle of Wight and Brownsea Island. Grays live almost everywhere else, from broadleaf woods to city parks and suburban gardens.

Both are active by day and build twig nests called dreys. Gray squirrels are generally bolder around people and spend more time on the ground. Red squirrels tend to stay higher in the trees and are shyer, which also helps them avoid predators such as the pine marten.

Their breeding is similar. Both species mate in late winter and again in summer when food is plentiful, and a female can raise one or two litters a year. Red squirrels are pregnant for about 38–39 days and usually have around three young; gray squirrels are pregnant for about 44 days and usually have two to four. In both, the young are born blind and hairless and leave the nest at around two months old.

Lifespans are also alike. In the wild, most squirrels of both species die young, often in their first winter, and those that survive usually live a few years. Red squirrels can reach about 7 years in the wild, and grays occasionally reach 10 years or more. Gray squirrels, being bigger and fatter, tend to survive hard winters better, another small edge over the reds.

Why gray squirrels replace red squirrels

The two species do not fight. Gray squirrels win by eating more of the available food, including acorns and nuts that reds bury, and by living at higher densities. Many grays also carry squirrelpox virus, which rarely harms them but usually kills reds within about two weeks. Together, these effects have pushed red squirrels out of most places that grays have reached. The full story is in why are red squirrels declining? and why are gray squirrels invasive in the UK?

Where can you see both?

The two species overlap where grays are spreading into red squirrel areas, such as parts of Cumbria, Northumberland, southern Scotland and Ireland, and in Piedmont and Lombardy in northern Italy. In most of southern England, Wales and lowland Scotland only grays are found, while in the Scottish Highlands, on Anglesey, Brownsea Island and the Isle of Wight, reds are the squirrels you are likely to meet.

Can they interbreed?

No. Red and gray squirrels belong to the same genus, Sciurus, but they are separate species that evolved on different continents, and there are no known hybrids between them.