The dietary habits of squirrels is fascinating!  What and how these animals eat is essential for the development of healthy forests and varies throughout the year.  There are even a couple of food items that they require which will really surprise you!

Have you ever wondered, “What do squirrels eat?”

Squirrels are opportunistic omnivores that primarily eat nuts (acorns, hickory, pecan), tree buds, grains, grasses and fungi.  Squirrels will also eat protein sources such as bird eggs, insects and small reptiles.  The exact diet of a squirrel is dependent upon both the species in question along with geographical location.

Let’s take a closer look at how the diet of a squirrel varies between different species and throughout the year.

Squirrels Are Omnivores

Squirrels are opportunistic eaters and their diets will vary based upon what food sources are available.  Some of the most common food sources for these animals are given below.

Tree Nuts

One of the primary food sources for squirrels is tree nuts.

Grey and Fox squirrels love to eat nuts from oak, walnut, hickory, and pecan trees.

Red Squirrels subsist primarily upon the nuts found within pine cones.  The heavy reliance upon this particular food source is why these animals are often referred to as “Pine Squirrels”.

Tree nuts are a significant portion of a squirrels diet but they are not available all year long.

While squirrels will create large caches of nuts when they are plentiful in the fall, these resources are usually completely consumed during winter and requires the animals to rely upon other food sources in the Spring and Summer.

Sometimes a squirrel will forget where they left a cache of nuts and some of these will sprout in the Spring and help the forest remain healthy!

Tree and Flower Buds

In the Spring squirrels will feast on the tender, nutrient dense budding flowers and fresh green shoots from their favorite trees and shrubs.

Some common tree buds that they enjoy include:

• Maple
• Hackberry
• Elms
• Dogwoods
• Wild Cherry
• Mulberry

If you are an avid gardener then you have probably watched your precious tulips being munched upon (or even dug up!) by squirrels looking for a Springtime meal.

Fungus and Lichen

I love eating mushrooms and so do squirrels!

While all squirrels eat mushrooms they are a primary part of the diet for flying squirrels and are heavily relied upon by pine squirrels.

Like so many things in nature, there is a special relationship between flying squirrels, the fungus that love and the health of the forest.

,The fungi eaten by flying squirrels, mycorrhizae, grows near the base of trees and helps promote the health of nitrogen fixing bacteria.  The nitrogen fixing bacteria help provide trees with essential nutrients trees that enables healthy growth.

When flying squirrels harvest this fungus they help spread the spores and distribute the fungus throughout the forest.

Insects, Moths and Worms

Insects are eaten in the summer and are probably especially important for juveniles.

Insects are plentiful, easy to catch and are typically high in protein.  This combination makes insects an ideal food source for young squirrels who are just starting their way through the world and need plenty of protein for rapid growth.

Birds and Eggs

Squirrels are opportunistic eaters and will chow down on bird eggs or even fledglings if they happen to come across an unprotected nest.  The most notorious species for eating birds are the Northern and Southern flying squirrels.

Flying squirrels spend most of their time in trees so they have more opportunity to come across nests.

The National Wildlife Federation states, “Southern flying squirrels are considered one of the most carnivorous squirrels because they supplement their diet with eggs, birds, and carrion.”

Meat

The meat eating behavior of squirrels varies significantly between species.

Female Fox and Grey squirrels will eat carrion to provide much needed protein while pregnant and nursing.

Pine squirrels have been reported to actively hunt chipmunks and even northern hare.

Ground squirrels routinely fight snakes that come to eat the young from their burrows.  Often the ground squirrels will kill the snake and eat it afterwards

Here is a GREAT article about the amazing defenses ground squirrels have against snakes!

Fruits

Squirrels are extremely fond of fleshy fruits like apples and peaches.  Depending upon the region and fruit, orchard owners will often report losing up to 20% of their harvest to squirrels and birds.

Many owners of fruit trees resort to picking fruits early when they are still not quire ripe just to avoid having the tree ravaged by hungry squirrels.

Two Surprising Foods!

There are two unexpected food categories for these animals and they are both based upon the fact that squirrels are members of the rodent family.

Let’s take a look!

Bones and Antlers

One surprising food item that needs to be addressed is the squirrel’s need for animal bones or antlers.

The defining characteristic of a rodent is the presence of front incisor teeth that never stop growing.  Rodents need hard substrates to gnaw upon.  The gnawing keeps the incisors sharp and prevents them from becoming overgrown.

An ideal substrate for squirrels to gnaw upon are the bones and antlers of other animals.  In addition to keeping their teeth in shape, the bones and antlers provide a rich source of calcium for the animals.

Poop

I bet you didn’t see this one coming!

All rodents practice “coprophagy” which involves eating their own feces.  Although this probably sounds disgusting, coprophagy is an essential practice.

When rodents eat food some of the essential digestive work that converts the food into absorbable nutrients is performed in the lower intestine.  The issue is that while the lower intestine can perform the conversion, it cannot absorb the nutrients.

In order for rodents to benefit from the digestive work performed by the lower intestine they must eat their poop so the nutrients can be absorbed in the upper intestines.

Should You Feed Squirrels Peanuts?

Peanuts are not a natural part of a squirrel’s diet and whether or not you should offer them to your furry friends is a point of debate.

Many wildlife specialists will tell you that peanuts are high in fat and are not healthy for wild animals.  Other folks will point out that the leading causes of squirrel mortality are predation, cold and lack of food.  I love my squirrels so I don’t mind putting a little extra food out for them, especially during winter months.

Peanuts should not be the primary food source for squirrels so if you do decide to feed them make sure their are other food options available.  You could always put up one of our picnic table squirrel feeders and let them eat corn!

Further Reading and Resources

The following wonderful resources were used as reference materials for this article.  If you would like to learn more about the dietary preferences of these amazing animals then please explore the links below!

• Reference 1
• Reference 2
• Reference 3
• Reference 4
• Reference 5
• Reference 6
• Reference 7
• Reference 8
• Reference 9
• Reference 10

Squirrels are among the most common wildlife that we see in urban environments and they generate a lot of curiosity with their behavior and antics.  People are especially fascinated with baby squirrels because, let’s be honest, they are absolutely adorable!  If you are excited about the thought of seeing some of these delightful itty bitty fur balls then you are probably wondering, “When do squirrels have babies?”

Squirrels have a litter of 2-4 babies, called kits or kittens, in February and March.  Older female squirrels will produce a second litter in August.  The timing of the births will vary based upon latitude and availability of food.  The babies will leave the nest at three months of age and reach full size nine months after being born.

The Months That Squirrels Have Babies

We are going to be specifically looking at the Eastern Grey squirrel for this article as it is one of the most common squirrel seen and asked about in urban environments.  Other species of squirrels (Fox, Red, Flying) follow similar patterns of reproductive behavior but with different breeding dates and gestation periods.

Eastern grey squirrels breed in late December through February in warm climates.  In colder climates the breeding season is delayed and occurs in January through March.  Grey squirrels have a second breeding season in May through June which extends into July in colder climates.

Grey squirrels will carry their babies for 44 days which results in the earliest baby squirrels being born in late January and the latest being born in April.  In the fall breeding season the babies will be born in June and July.

Breeding Month	Gestation	Birth Month
December	44 days	January
January	44 days	February
February	44 days	March
March	44 days	April
May	44 days	June
June	44 days	July
July	44 days	August

By taking the differences in climate into account you can see that squirrels in Florida will have babies in late January and June while squirrels in Michigan will have babies in April and August.

The numbers and dates presented above are general ranges but they can vary dramatically based on environmental conditions.  An article published in the Journal of Ecology by John Gurnell in 1996 showed a strong statistical correlation between both food availability and winter severity with the breeding patterns of grey squirrels.  To quote from the article’s abstract:

“In good seed years, breeding starts in December, in poor seed years the start of breeding is deferred until the spring. There was no or very little spring breeding in 5 years when food supplies were poor.” 

Here is a more detailed article describing what squirrels eat that shows the importance of different food sources.

How Many Babies Are in a Litter?

Grey squirrels average three babies per litter with a maximum liter size of eight. These babies, called kits or kittens, are born blind, deaf, and furless, like most other species of rodents. Their ears are also folded against their skull and they are completely helpless.  The kits weigh about 15 grams which is about the same weight as two tablespoons of flour.

The mother remains in the nest with the babies, where she cares for them by herself. They are fed every few hours and require constant care by their mother for several weeks.

When Do Baby Squirrels Leave the Nest?

The timeline for the development of young squirrels can be described as follows

• 1-2 weeks old: Pink skin, eyes and ears closed. Kits are nursing.
• 2-3 weeks old: Dark skin, eyes and ears closed. Kits are nursing.
• 3-4 weeks old: Fuzz type fur, eyes and ears closed. Kits are nursing.
• 4-5 weeks old: Fur development, eyes and ears open.  Kits are nursing.
• 6-7 weeks old: Bushy tail and looks like a miniature adult. Kits are nursing.
• 7 weeks old: Weaning begins and solid food is introduced.
• 10 weeks old: Weaning is complete.
• 11 weeks old: Young squirrels leave the nest and are independent.

Baby squirrels become fully independent and are able to leave the nest roughly three months after being born.  This means that the squirrels that are born in late January will start running around your yard towards the end of April while ones born from the summer breeding season will emerge in the September/October timeframe.  

Depending on the number of squirrels in the immediate area and available nesting sites, the young squirrels may try to build their nest close to their mother. Grey squirrels are not territorial and most stay within two miles of their home nest. If the area is crowded with other squirrels, the young squirrels may be forced to travel further away to establish their nest.

Squirrels born from the summer mating season have little time to prepare for winter by fattening up and caching nuts than squirrels born in the spring. As a result, the long term survival rate for summer babies is typically lower than spring babies. The other major factor that influences how long squirrels live is the abundance of predators.

How Old Are Squirrels When They Mate?

Young squirrels reach their full adult size and mass around 9 months of age but sexual maturity takes longer to obtain.

Females grey squirrels typically reach sexual maturity when they are about 15 months old while male squirrels are sexually mature closer to 12 months old but will be delayed if in the presence of dominate males.  This means that a female squirrel born in November would be ready to mate in the following summer season.

The reproductive cycle of male grey squirrels is interesting and is defined through testicular development.  Sexually active male squirrels have very pronounced testicles that go through two seasons of testicular regression where the size of their testicles shrink by up to 90%.  These times of regression correspond to seasons where females are not breeding and are thought to be a way to conserve energy.

The thought that testicular regression is an energy conservation mechanism is supported by a study that showed males which were extremely well fed in an enclosed environment did not undergo regression.  Further supporting this idea is another study which showed regression was prolonged when food was scarce.

Squirrels do not mate for life and are quite promiscuous.  Males will mate with multiple females and females will mate with multiple males.  It is not uncommon for a female squirrel to have a litter where the kits are sired by multiple fathers.  The mating process involves elaborate chases where males pursue the females and scare away other males.

I love feeding the squirrels and watching my dogs chase them in circles. Most of the time the critters are just scampering around like normal and chattering away at my dogs.  Sometimes though, you will see a squirrel that is acting incredibly aggressive towards humans or that is stumbling around when it walks.  Both of these behaviors are similar to what is seen in rabid wild animals. It made me ask the question, “Do squirrels carry rabies?”

Squirrels do not carry rabies but do carry other diseases.  If you see a squirrel behaving erratically then there are multiple reasons to explain the odd behavior other than rabies.

The Center for Disease Control states that squirrels are extremely unlikely to carry the rabies virus.  While rabies is certainly a dangerous disease for humans it is actually quite rare in the US population.  On average there are only 2-3 reports of rabies being transmitted to humans in this country each year.

Here is a link to the rather short list of all US rabies cases since 1951.  In almost all cases of infection the disease was transmitted to a human through contact with bats.

Squirrels May Carry Other Diseases

Just because you don’t have to worry about rabies doesn’t mean that it is safe to handle squirrels as they can spread tularemia and leptospirosis through their bites.

Tularemia is a bacterial disease that attacks the skin and lymph nodes. The lymph nodes may swell while ulcers may develop at the site of the bite. The symptoms may develop within several days up to two weeks.

Leptospirosis is also a bacterial disease. Those infected with this disease may experience headaches, fever, vomiting, rashes, and jaundice. Leptospirosis may also lead to kidney damage.

In rare cases, squirrels may also spread ringworm. Ringworm is not a worm. It is a fungal infection that primarily affects the skin. A red rash with a ring-like appearance may develop and become irritated. This infection may spread through contact with a squirrel and is less likely to spread as a result of a bite.

While squirrels rarely pass diseases to humans and pets, it is still important to visit a doctor if you are unfortunate enough to getting bitten to take preventative action against infections.

Why Is a Squirrel Acting Erratic?

One symptom people associate with rabid animals is the animal acting erratically.  Normally if you see a wild animal that has a staggering gait or is approaching you in an aggressive manner then you should be concerned about the animal being rabid.  However, there are many reasons to explain this behavior is squirrels other than rabies.

Aggressively Seeking Food

Squirrels are smart animals.  If one of their standard food sources comes from people sitting on park benches and feeding them peanuts then they are going to assume that anyone sitting on those benches has some food for them.

It is not uncommon for squirrels that are used to being hand fed by humans to run towards people and even start climbing on them and going through their pockets.  These squirrels can become quite aggressive at times and have been known to accidentally scratch people with their sharp claws as they climb around them.

Intoxicated

Squirrels have an extremely diverse diet that often includes fruits and vegetables.  If a squirrel eats fruit has fermented then the little guy can get drunk and will be wobbling around as it walks.

You can head over to YouTube and do a search for “Drunk Squirrels” and see how common this is.  There are videos of squirrels getting intoxicated from fermented pears, crabapples, cherries, apples and pumpkins.

Poisoned/Injured

Another reason for erratic behavior in a squirrel is if it is in distress from being poisoned or attacked by a predator.

There are a lot of people who dislike squirrels, especially ground squirrels, and resort to the use of poisons to eliminate them.  A poisoned squirrel is going to be suffering and walking/acting in a manner that is not normal.  Unfortunately there is nothing you can do to help a squirrel that has been poisoned.

Squirrels have many predators and are under frequent attack.  If you see a squirrel that is walking or acting strangely then there is a good chance that it has escaped a predatory attack but was injured in the process.  If you see an injured squirrel you can put some food and water into a sheltered location for it but do not try to catch it with your bare hands.

 

I am always blown away by how many types of squirrels there are in the world.  When I started this project I thought I was just going to be talking about those grey and fox squirrels that were running around in the trees in my backyard.

It turns out that the term squirrel covers critters as small as chipmunks, as large as groundhogs and even has a bunch of giants! There are a dozen different species that are formally named as giant squirrels.  Four of the giants belong to the Ratufinae Subfamily and eight of the giants are flying squirrels from the Sciurinae Subfamily.

All of these animals exist outside of the United States so you are going to have to do some serious traveling if you want to see any of them in the wild.  Nevertheless, it is always fun to read about interesting animals so I wanted to give a complete breakdown of all twelve giant squirrels in the world.

Let’s get started!

[Read more…]