Flying squirrels are one of my favorite animals and I get a smile on my face every time I get lucky enough to see one. I did some research into these animals to answer some of my basic questions and thought other folks might benefit as well.
One of the questions I researched was, “What do Flying Squirrels Eat?”
The answer is, “Northern Flying Squirrels primarily eat truffles while Southern Flying Squirrels primarily eat acorns.”
Keep reading and you will learn a few more tidbits from some pretty interesting academic studies!
The Two Primary Species of Flying Squirrels
While there are several types of flying squirrels in the world the two that are the most common in North America are the Northern Flying Squirrel (Glaucomys Sabrinus) and the Southern Flying Squirrel (Glaucomys Volans). These two species account for at least 95% of all of the flying squirrels in North America.
For sake of completeness it should be noted that there are two subspecies of the Northern Flying Squirrel (Carolina and Virginia). There is also a third completely different species that is only found in a small stretch of redwood forests, the Humboldt’s Flying Squirrel.
This article will focus on the dietary habits of the two most populous species, the Northern and Southern.
How Scientists Determine What Different Squirrels Eat
There are three primary methods that researchers use to determine the diets of wild animals.
The most common method is to find piles of animal poop (scat) and pick through it to identify any undigested materials. This method is the easiest to conduct but can lead to inconclusive or incomplete results. The results can be inconclusive as not all undigested matter is easily identifiable and can be incomplete as it would not detect any food that was completely digested.
The second most common method is field observations of the animal while it is eating. This method can be challenging in the case of flying squirrels as they feed at night which makes physical observations difficult.
The least common method, but most conclusive, is to capture the animal, kill it and then examine the stomach contents. This method is only used under special circumstances due to the ethical concerns of killing wild animals for research purposes.
The Diet of Northern Flying Squirrels
I discovered three studies concerning the diet of Northern Flying Squirrels and each of them determined that hypogeous fungi was a primary food source.
Don’t worry if you are not familiar with the term “hypogeous fungi” as all it means is a fungus that fruits underground. In general terms these are considered truffles which grow just under the decomposing leaves on the forest floor.
The focus of the studies was to determine what else this species eats to balance out their diets as well as how the food preferences change during the seasons.
A 1997 study of flying squirrels in Oregon concluded that other food sources included epigeous fungi, fruits and seeds, and conifer seedlings. The term epigeous fungi refers to fungus that flowers above the ground, what you and I would call mushrooms.
A 1997 study of these animals in Idaho concluded that supplemental summer foods included multiple types of mushrooms while supplemental winter foods included multiple types of lichens.
A 2001 study of the Virginia subspecies concluded that the spring diet was supplemented with tree buds and lichens while the fall diet was supplemented with mushrooms and beechnuts.
The Diet of Southern Flying Squirrels
The three studies I found concerning the diet of Southern Flying Squirrels all concluded that the primary food source for the species was acorns.
A 2014 study determined that acorns from White Oaks were the most popular and constituted about half of their diet. Acorns from Water Oaks and Black Oaks were next in popularity. It was also determined that the squirrels would eat the fruits from Flowering Dogwoods and Hickory nuts but that these were not really preferred.
A 1998 study determined that this species had a dynamic foraging system that was temperature dependent. When temperatures were warm to mild the squirrels would eat acorns and stash away hickory nuts. As soon as the temperature got really cold the squirrels would start eating the hickory nuts.
A 1990 study that took place in South Carolina determined that supplemental food sources included pine seeds, unidentified black- and red-colored plant cells, American holly fruit, unidentified plant cells, tree moss, fungal spores and hickory seeds. Animal matter, consisting exclusively of insects, occurred in 11% of the samples.