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How Big Are Squirrels? Weights and Sizes by Species

A grey squirrel weighs about a pound; a flying squirrel weighs two ounces. Sizes across the common species, and why the tail is half the length.

By Zakaria 4 min read Save to Pinterest — opens Pinterest in a new tab
A grey squirrel standing upright on its hind legs in autumn grass, full body and tail visible
Photo: Erik Chistov, Pexels License, via Pexels
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A grey squirrel is about a pound. A flying squirrel in the same wood weighs two ounces — a tenth of a fox squirrel, and the reason most people never notice it is there.

By species

Weight and length across the common species
SpeciesWeightBodyTotal with tail
Fox squirrel17–35 oz10–15 in20–28 in
Eastern grey14–21 oz9–12 in16–22 in
Western grey12–33 oz10–12 in18–24 in
Douglas squirrel5–11 oz6–8 in11–14 in
Red squirrel5–9 oz7–8 in11–14 in
Northern flying4–6 oz5–7 in10–12 in
Southern flying2–3 oz4–5 in8–10 in
Chipmunk1–5 oz4–6 in7–10 in
Ground squirrel9–18 oz9–11 in15–20 in

The range within a species is real. A fox squirrel in good autumn condition in the Midwest is a substantially bigger animal than one in a poor mast year further south.

Grey or fox, at a distance

They overlap in size, and people mix them up constantly.

Fox squirrels are heavier, rustier and more orange underneath, and spend more time on the ground and in open woodland. Greys are smaller and greyer with a white belly, and stick closer to cover.

Where both occur, the fox squirrel is usually the one crossing open lawn without hurrying.

Why the tail is half of it

Not decorative. In a tree squirrel the tail is roughly 40 to 50 per cent of total length, and it does at least five jobs:

  • Counterbalance on a branch and during a leap
  • Rudder and parachute in a fall — squirrels survive falls that should kill them
  • Sunshade, held over the back in heat
  • Blanket, wrapped around the body in cold
  • Signal flag — the flick that warns other squirrels and tells a ground predator it has been seen

A squirrel that has lost part of its tail to a predator or a fall manages, but climbs and jumps noticeably less confidently.

Through the year

  • Autumn: feeding hard, laying down fat. Up to 20% heavier by early winter
  • Winter: living on reserves and cached food. No hibernation in tree squirrels
  • Late winter and spring: weight drops, and breeding takes more out of females
  • Summer: lightest, and moulted into a thinner coat, which makes them look smaller than they are

A plump squirrel in November is a healthy squirrel. A thin one in March is normal too.

From birth to full size

Growing up
AgeSize
Birth~1 in, ¼–½ oz. Blind, deaf, hairless
4 weeksEyes open, furred
6–7 weeksFirst trips out of the nest
10–12 weeksWeaned
~6 monthsClose to adult size
1 yearFull adult weight

That table is genuinely useful if you find a young squirrel on the ground: hairless or eyes-closed means it needs help, while a furred, alert animal roughly hand-sized is at the stage where it should be out exploring.

Males and females

Close to the same size, with no reliable difference visible at a distance — unusual among mammals, and a consequence of a social system where males do not hold territories or defend harems.

Sexing a squirrel by eye is not realistic outside the breeding season, when a male’s anatomy becomes obvious.

For scale

  • Southern flying squirrel: about the weight of a AA battery times two
  • Red squirrel: a large apple
  • Grey squirrel: a tin of beans
  • Fox squirrel: up to two tins
  • Indian giant squirrel, the world’s largest: three feet including tail, four pounds plus

Common questions

How much does a squirrel weigh?

It depends entirely on the species. An eastern grey squirrel weighs about 14 to 21 ounces, roughly a pound, and a fox squirrel is the heaviest North American tree squirrel at 17 to 35 ounces. A red squirrel is much smaller at 5 to 9 ounces, and a southern flying squirrel weighs only about 2 to 3 ounces — less than a tenth of a fox squirrel. Chipmunks, which people often group with squirrels, weigh 1 to 5 ounces.

How long is a squirrel including its tail?

Roughly double the body length, because the tail accounts for close to half the total. An eastern grey squirrel is about 9 to 12 inches in the body with a tail of 7 to 10 inches, giving 16 to 22 inches overall. A fox squirrel reaches 20 to 28 inches in total. That proportion is functional rather than decorative: the tail works as a counterbalance when climbing, a rudder and parachute in a fall, a sunshade, a blanket in winter and a signalling flag.

Which is the biggest squirrel in North America?

The fox squirrel, at 17 to 35 ounces and up to 28 inches including the tail. It is noticeably heavier and more rust-coloured than the grey squirrel it is often confused with, and it tends to spend more time on the ground and in open woodland. Worldwide the largest squirrels are the Indian giant squirrels, which reach three feet including the tail and weigh four pounds or more.

Do squirrels get heavier in winter?

Yes, noticeably. Grey and fox squirrels put on fat through autumn and can be twenty per cent heavier by early winter than they were in summer, which matters because they do not hibernate and have to sit out cold spells on stored reserves and cached food. They lose it again through late winter and the breeding season. A squirrel that looks unusually plump in November is doing exactly what it should be.

How big are baby squirrels?

About an inch long and a quarter to half an ounce at birth — blind, deaf and hairless. They open their eyes at around four weeks, first leave the nest at six to seven weeks, and are weaned by ten to twelve. A kit reaches something close to adult size by about six months, though full weight comes later. The size is one way of judging whether a young squirrel found on the ground is old enough to be out and exploring.

Are male and female squirrels different sizes?

Barely, which is unusual among mammals. Male and female tree squirrels are close to the same size and weight, with no reliable visual difference between them at a distance, so sexing a squirrel by eye is not realistic outside the breeding season. This is different from many mammals where males are substantially larger, and it reflects a social system in which males do not defend territories or harems.

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