Squirrels: Major Groups, Anatomy, Behavioural Traits and Their ‘Obsession’ with Nuts

Squirrels are animals most of us have seen at least once. They live almost everywhere in the world, in forests, grasslands, parks and even backyards. Scientists group them under a family called Sciuridae. You’ll find them on every continent except Antarctica and Australia. People love watching them because they’re quick, clever and always seem to be doing something with food.

Table of Contents: 

• Major Groups of Squirrels
• The Anatomy of a Squirrel
• Behavioural Traits of Squirrels
• Squirrels’ ‘Obsession’ with Nuts

Major Groups of Squirrels

There are many different types of squirrels, more than 280 species in total. The ones most people know are tree squirrels, like the grey squirrel and the red squirrel. These guys are built for climbing. Their back legs are strong and their claws are sharp enough to grip tree bark easily.

Then there are ground squirrels, which dig burrows and live in open fields and dry areas. Flying squirrels are a bit of a surprise; they don't actually fly. Instead, they glide from tree to tree using a flap of skin that stretches between their front and back legs. There are over 50 kinds of flying squirrels alone.

Chipmunks, groundhogs, prairie dogs and marmots are all squirrels too, even if we don't always think of them that way. In South Asia, the Indian palm squirrel is a common sight in gardens and parks. The squirrel family is really quite large and varied.

The Anatomy of a Squirrel

Squirrels have bodies that are well-suited to the way they live. Their front teeth never stop growing, which is handy because they spend a lot of time chewing through hard shells. These teeth are designed cleverly, hard on the front and softer at the back, so they naturally stay sharp on their own. Their eyes sit high on their heads and face outward, which means they can see almost all the way around without turning their heads. That helps them spot birds of prey and other predators quickly.

The bushy tail is one of the most recognisable things about a squirrel and it does a lot more than look good. It helps them stay balanced while jumping between branches, keeps them warm in cold weather, helps break a fall and is even used to send signals to other squirrels. Their front paws are surprisingly nimble. They can hold a nut and turn it around to find the best angle to bite. Their back legs are powerful enough to launch them across large gaps between trees.

Behavioural Traits of Squirrels

Squirrels are daytime animals. They’re usually most active in the morning and again in the late afternoon. They can be quite protective of their food and their nesting spots. If another squirrel, or any threat, comes too close, they'll make noise about it. They have a whole set of sounds they use to communicate, including sharp alarm calls that warn nearby squirrels of danger.

In colder parts of the world, some squirrels slow right down or go into a deep sleep during winter. Ground squirrels and marmots are real hibernators; their body temperature drops and they live off the fat they've built up. Tree squirrels don't hibernate, but they do stay tucked away more during really bad weather.

Squirrels’ ‘Obsession’ with Nuts

Perhaps no behavioural trait is more associated with squirrels than their caching of nuts and seeds-a strategy known as scatter-hoarding. Instead of keeping all their food in one place, they bury it in hundreds, sometimes thousands, of separate spots. This way, if another animal finds one stash, they haven't lost everything. It's called scatter-hoarding and it works really well.

What’s even more impressive is that squirrels actually remember where most of those hiding spots are, even months later. They use spatial memory, a kind of mental map, to find their buried food when they need it.

They’re also sneaky about it. If a squirrel notices another animal watching while it buries a nut, it might pretend to bury something and then move the real nut somewhere else. That’s a level of thinking most people wouldn't expect from a small furry animal.

The side effect of all this burying is that forests benefit enormously. A lot of those nuts never get dug up again and they eventually grow into trees. Oak forests especially have squirrels to thank for a good deal of their growth and spread.