All of the creatures we feature for Animal of the Month are unique, but this month we had a really unusual star – squirrels; specifically, the Eastern grey squirrel. That’s because squirrels are not pets, but our clinic does see them under special circumstances. Squirrels are amazing animals and after our Dr. Evan Mavromatis recently removed a pellet from the head of a squirrel named Grace, we were inspired to shine the spotlight on squirrels as our Animal Of The Month for June. Did you know?:

• The common word “squirrel” is derived from the common name for the Family of rodents Sciuridae in scientific classification.
• There are 22 species of squirrels in the Family Sciuridae that are native to Canada. Six of them are tree-dwelling squirrels and the other 16 species are ground dwellers – including chipmunks, marmots and prairie dogs.
• One of most common squirrels seen in southern Ontario – where our clinic is located – is the Eastern grey squirrel (Sciurus carolinensis), which we are going to focus on as our Animal Of The Month for June.
• Eastern grey squirrels have a huge natural range. They are found in eastern North America stretching from Florida to eastern Texas and then northward to southern Ontario, Quebec, Manitoba and parts of New Brunswick and Saskatchewan.
• There are introduced North American populations of Eastern grey squirrels in Nova Scotia, Alberta, BC (including Vancouver Island), Montana, Oregon, Washington State and California.
• There are also introduced populations of Eastern grey squirrels in the UK, Ireland and Italy, where they have caused the local extinction (extirpation) of native red squirrels by out-competing them for resources and habitat while also spreading disease to them.
• Eastern grey squirrels were also introduced in South Africa. But much of the indigenous vegetation doesn’t meet their food and habitat requirements, so their populations are mostly limited to oak trees and commercial pine plantations.
• The Eastern grey squirrel has the dubious “honour” of landing on the “100 of the World’s Worst Invasive Alien Species” list, according to the Global Invasive Species Database.
• There are three different types of squirrels in the Sciuridae family – tree, ground and flying. Eastern grey squirrels are tree squirrels, which means they spend much of their time in trees.
• The ideal Eastern grey squirrel habitat is a mature hardwood or mixed forest. But they have successfully adapted to living side-by-side with humans in urban settings.
• Eastern grey squirrels can live in two different types of homes in the trees. They can make a home in a tree cavity or they will make an open nest out of twigs and leaves high off the ground in the junction where two or more branches meet.
• But if there are holes in a roof, soffit or eaves, Eastern grey squirrels may view them as being similar to tree cavities and take up residence in a person’s home.
• The Eastern grey squirrel is considered a medium-sized when compared with other squirrel species. From tip to tail, they are about 20 inches long – with about half of that length consisting of their big bushy tails.
• Eastern grey squirrels have big black eyes on the sides of their heads, which gives them a wide visual field in order to detect predators. Their ears are small and upright.
• Eastern grey squirrels have mouths that are just on the underside of their faces. They also have fine sensitive whiskers on their muzzles, which help them navigate in the dark.
• As their name suggests, Eastern grey squirrels have predominently grey fur on their heads, backs, legs and tails – this fur may also have reddish tones to it. The fur on their undersides is a whitish colour.
• But not all Eastern grey squirrels are grey. Some have black fur all over their bodies and there are a couple of theories as to why this colour morph exists.
• Black Eastern grey squirrels are common in the northern part of their natural range, while they are not found at all in the southern-most parts of their range.
• One theory suggests this is an evolutionary adaptation that gives Eastern grey squirrels with this black fur morph an edge on surviving northern winters as their dark fur traps heat.
• But researchers recently found a gene variant in black Eastern grey squirrels that was identical to one found in the naturally darker fox squirrels, suggesting interbreeding between the two species may be responsible for the morph.
• There are no obvious physical differences between males and females, which means Eastern grey squirrels are considered to be a monomorphic species.
• The large bushy tail is a lot more than just a distinct physical characteristic of the Eastern grey squirrel. It’s a communication tool, rudder, defense mechanism and more!
• The tail is such a prominent and important physical feature that the first part of the Eastern grey squirrel’s scientific name, Sciurus, loosely translates from Greek to mean the squirrel is in the shadow of her tail (skia = shadow, oura = tail).
• In addition to their various vocalizations, Eastern grey squirrels use their tails to communicate their mood with each other and with other animals. They can often be seen flicking their tails in agitation at predators.
• Researchers also recently discovered that Eastern grey squirrels also use their tail positions to communicate aggression and their position within their dominance hierarchy.
• Their tails can be life savers – literally. If a predator grabs them by the tail, Eastern grey squirrels have the ability to lose the fur, skin and even some of their vertebrae (small back bones) to escape.
• But the lost part of the tail never grows back. So if you see an Eastern grey squirrel with a partial tail, it’s likely she survived an attack from a predator.
• It’s an all-weather tail. Eastern grey squirrels can position their tails up along their backs to act as an umbrella, shielding them from rain and the scorching sun. Their tails are also blankets that they can curl around them to keep them warm.
• Eastern grey squirrels can often be seen tightrope-walking across wires and other thin passageways. Their tails help them balance as they make their way along narrow passages or hang on to awkward surfaces.
• Their tails are also built in parachutes! If Eastern grey squirrels jump or drop down from a considerable height, they use their tails to slow their descent.
• While not famous for their swimming ability, Eastern grey squirrels can swim if they need to – and their tails act as their own personal rudders.
• It’s easy to see – even with only casual observation – that Eastern grey squirrels possess incredible agility, intelligence, speed and tenacity.
• Eastern grey squirrels have legs and feet that allow for some pretty fancy footwork. Their front feet have four toes (or fingers). Five longer toes are on their hind feet, which resemble human hands.
• All four of their hairy feet have long, curved claws which allow the Eastern grey squirrel to climb and hang on to trees and other surfaces.
• Eastern grey squirrels have very strong hind legs. They have double-jointed ankles and can rotate their hind feet 180 degrees, which allows them to climb down from trees and other surfaces head first.
• What do Eastern grey squirrels have in common with cats? They both always land on their feet! But how do they do this?
• In addition to their rudder-like tail, Eastern grey squirrels are light and small with a low center of gravity and can flatten their bodies when they jump or drop from great heights.
• Their body shape and weight distribution naturally forces Eastern grey squirrels to jump or fall with their feet facing downward. They will extend their legs out in front of them to brace themselves for landing.
• Because they are prey for many – including (but not limited to) – humans, foxes, lynx, bobcats, wolves, mink, domestic dogs and cats and birds of prey – Eastern grey squirrels need to be fast on their feet and make split-second decisions.
• Eastern grey squirrels can jump up vertically to a height of around 1.2 metres (4′) and horizontally to a distance of around 2.4 metres (8′). When running, they can reach estimated speeds of between 25-32 km/h (15-20 miles/hour).
• Most of the Eastern grey squirrel diet consists of plant matter – which includes flowers, buds, fruit and mushrooms – but they mainly eat a variety of nuts and seeds.
• Eastern grey squirrels are actually omnivores as they will also eat animal matter; including insects, bird eggs and nestlings.
• Eastern grey squirrels don’t hibernate in the winter. So in autumn, they will gather and store food to get them through the winter months.
• Known as scatter hoarders, Eastern grey squirrels will store huge amounts of food by burying them in the soil in various locations.
• Because they are known to steal buried food from one another, Eastern grey squirrels have come up with a couple of tricks to try to protect their food caches.
• If an Eastern grey squirrel knows she is being watched by others, she will pretend to bury food in one location. She will then bury her food in a different place away from prying eyes.
• Storing food in open areas is dangerous because it makes Eastern grey squirrels more vulnerable to predators. But they will take the chance and bury food out in the open because the threat of predators serves as a theft deterrent.
• But how do Eastern grey squirrels find all of the food that they’ve buried? They do it through a combination of memory, their keen sense of smell and an organization technique called “spatial chunking.”
• California researchers studying the fox squirrel found that they will organize their food stores according to nut type. For example, they will bury walnuts in one general area, hazelnuts in another, etc. This is spatial chunking.
• Researchers suggest that Eastern grey squirrels also use spatial chunking when hoarding food for winter as they have similar food habits to fox squirrels. It is believed spatial chunking helps them remember where their food is buried.
• Eastern grey squirrels play a huge part in forest regeneration. While they retrieve the vast majority of the hoarded nuts and seeds they buried for winter, some are abandoned and will germinate.Between dodging their many predators, vehicles and other dangers, wild Eastern grey squirrels typically live less than six years. But there are reports of Eastern grey squirrels as old as 13 being found in the wild.
• In captivity, Eastern grey squirrels can live an average of between 15-20 years. But we want to emphasize that squirrels are not pets!

We also want to emphasize that our clinic does not see wildlife. If you have an urgent matter regarding wildlife, please contact our friends at Toronto Wildlife Centre at 416-631-0662 or Shades of Hope Wildlife Refuge at 705-437-4654.