My yard is full of Eastern grey squirrels, so when I heard movement in the attic late one night, my first thought was – could it be a squirrel? I mean as interesting as I find them, I don’t want these guys living in my house! So anyway, long story short, it wasn’t a squirrel that I heard. It was rats.
That really sucked but is another story.
That whole adventure got me wondering about what squirrels do in the evening. The big question of course was, “Are squirrels nocturnal?” I did a little research and this is what I learned.
Squirrels are not nocturnal creatures. Tree and ground squirrels are diurnal animals, and like humans, they are active during the daytime. The activity pattern of squirrels during the day depends heavily upon the type of squirrel and time of year.
How Do We Know That Squirrels Are Not Nocturnal?
It turns out that scientists LOVE to study squirrels. There have been extensive scientific studies on the activity patterns of squirrels, some of which are highlighted below.
Scientific studies of the fox squirrel have determined that they stay in their nests during the evening, leave the nests at dawn and return at dusk. This pattern remained consistent throughout the seasons as the hours of daylight changed. Even when fox squirrels left their nests they were not very active as they spent most of their time just sitting in the trees.
Scientific studies of grey squirrels had similar findings as for fox squirrels with a few notable differences. Grey squirrels would leave their nests about 20-30 minutes before sunrise and return about 20-30 minutes after sunset. These squirrels would have flurries of activity in the morning and late afternoon with a period of rest in between. The pattern of increased activity at dawn and dusk for grey squirrels has caused some studies to label them as crepuscular instead of diurnal.
Scientific studies of American red squirrels were consistent with diurnal activity.
European Ground squirrels come out a few hours after sunrise and return to their burrows a few hours before sunset.
The One Exception is Flying Squirrels
Flying squirrels are the exception to the rule of nighttime activity. Studies of the nighttime activity of Northern flying squirrels and that of Japanese flying squirrels both document strong nocturnal behavior. As might be expected, under extreme cold winter conditions the flying squirrels don’t stay out very late at night and prefer to stay in the warmth of their nests.
Because flying squirrels are nocturnal many people do not realize that these creatures are living nearby! Flying squirrels are actually pretty common but you typically will not see them unless you go out of your way to look for them. If you haven’t seen a flying squirrel before then the video below shows them in action at night!
Why Are Squirrels Diurnal?
Most animals will evolve to be diurnal or nocturnal, depending on their physical characteristics and strengths. In the case of squirrels, they have excellent daytime vision. Their night vision is extremely poor and they’d be exposed to all kinds of danger if they chose to be active during the night.
As far as their day time vision is concerned, squirrels have an excellent focal vision and their peripheral vision is also very sharp. This allows a squirrel to react quickly to threats in its immediate environment. Without this, they would not be able to exhibit any of the quick reflexes associated with them and would not be able to protect themselves against predators or forage for food.
A study on nocturnal versus diurnal habits of animals drew a similar conclusion. It stated that an animal’s daily activity patterns are related to their growth and survival. Some of the factors that help determine diurnal and nocturnal habits are a risk from predators, availability of food, and the efficiency with which the available food can be acquired.
Given its dependence on its vision, a squirrel would be rendered quite helpless during the night time. They would not be able to detect predators, they would not be able to hunt for food, and they would not be able to find their way back to their nests.
Of course with flying squirrels there is an exception as the rod and cone structure of their eyes allows them to see very well at night.
Where Do Squirrels Go at Night?
Tree squirrels (grey, fox, red) spend their nights sleeping in a nest located in a tree. The nests are either built out of leaves and twigs (called a Drey) or are hollowed out cavities within the tree (called a Den). A squirrel will sometimes make a nest in your attic if there are no nesting sites available in the trees near your home. To help solve this problem you can put up commercial squirrel nesting boxes outside.
Ground squirrels spend their nights sleeping in a burrow. Ground squirrels burrows are complicated tunnel systems that can often house many families.
Flying squirrels will spend their nights foraging and gliding from tree to tree.
To Sum It Up
Nearly all species of squirrels are diurnal. The flying squirrel is the only exception to this rule and leads a nocturnal lifestyle instead. You could consider a squirrel’s daytime versus nighttime habits as a classic example of ‘Survival of the fittest’. Thanks to the power of sight, these rodents can make up for their small size and protect themselves against predators while looking for food in order to grow and thrive.