Figuring out why squirrels act like they do can be a fun challenge. Sometimes they act loving and playful with each other but other times they are aggressive and chase other squirrels away. So what gives with these critters? Are squirrels territorial or do they just like some squirrels more than others? I did a little research and was surprised by all of the information that I found. Here is what I learned:
The common tree squirrels (Grey and Fox) are not territorial. The American Red and California Ground squirrels are extremely territorial. Flying squirrels will exhibit territorial behavior if there is pressure for nesting locations. The degree of territorial defense also varies based upon the sex of the squirrel and the presence of babies.
If we look at the territorial behavior for some of these guys in detail then how they act starts making sense.
American Red Squirrels Are Territorial
There are three different species that are referred to as American Red Squirrels and they are all territorial. These squirrels are not the same as those cute little Eurasian Red Squirrels that the British are so nuts about.
Red squirrels have a territory of about 1 hectare (2.47 acres) but that value varies based upon the specific species and the type of forest they inhabit.
The defense of the territory is essential for a Red squirrels survival. Red squirrels eat a diet that primarily consists of the seeds from conifers. The squirrels will collect all of the cones they can find and store them in a giant pile called a midden. Squirrels are industrious and middens will often be huge. Middens can easily be thirteen meters in diameter, fifty centimeters in depth and hold enough food for years.
When a Red squirrel defends its territory what it is really doing is protecting the extremely valuable midden that it has worked so hard to produce.
An interesting study from the University of Alberta looked at how mother red squirrels dealt with territorial issues with their offspring. Most mothers will raise a litter and the young squirrels move away (typically about 70-80 meters) to establish their own territories. In some cases the mother will share part of a territory and up to a third of mothers will completely give up her established territory in an effort to increase the survival odds of the young squirrels.
A different species of squirrel that survives mostly on conifer seeds, the cute ear tufted Abert Squirrel, is not territorial at all. However, the Albert squirrel does not create middens and instead searches for food on a year round basis.
Flying Squirrels Go With The Flow
There are two types of Flying squirrel in the US, the Northern and Southern. Both types of flying squirrels exhibit a mixed pattern of territorial behavior.
For both species the males are completely non-territorial while the females exhibit a mixed degree of territorial defense. The territorial behavior of female Flying squirrels appears to be driven by the need to protect prime nesting sites to raise babies.
That being said, female Southern Flying squirrels will share a nesting site if it is large enough for multiple litters. According to the Maryland Department of Natural Resources: “Southern flying squirrels usually make their nests in natural tree cavities or old woodpecker holes, 15-20 feet up a tree. These nests can hold either a single female or a maternal colony of several females and their young.”
Similar nest sharing behavior has also been reported for Northern Flying squirrels by the University of Michigan.
Both species of Flying squirrels get real friendly with each other in the winter when they all pile into nests together to keep warm through shared body heat while they sleep.
Basically Flying squirrels are a friendly bunch that share what they have but a female will fight for a prime nesting spot if it is only big enough for her and her litter.
California Ground Squirrels Protect Their Burrows
The territorial behavior of California Ground squirrels is interesting. Males are the territorial sex and will aggressively maintain a home range that excludes other males. Females are protective of their burrows but their aggression is mainly correlated to the vulnerability of their babies.
The territorial range for these squirrels is typically within 75 yards of their burrows.
The territorial behavior of Ground squirrels is most likely related to the importance of their protective burrows. The burrows that these squirrels create are extensive and take a lot of time and energy to build. The burrow is essential for the squirrels survival as a way to escape predators. The burrow is an incredibly important asset and the squirrels will fight to protect it.
Despite the territorial nature of Ground squirrels they do have colonies and communities that share the burrow. This is an advantageous situation as a community will work together to spot predators. Some species of Ground squirrels hibernate in the winter and seal themselves into the burrow with other squirrels to stay warm.
The ability of Ground squirrels to work together despite their territorial nature is well documented in the defense of burrows against snakes. Here is a great example of African Ground squirrels chasing a cobra out of their territory.
Grey and Fox Squirrels Are Not Territorial
The most common varieties of squirrels, the Grey and Fox, are not territorial animals. While you will find females that are protective of their nests the males don’t really care who is hanging around. There has been speculation that the black varieties of these squirrels might be more aggressive as a side effect of the genetic mutation that gives them their distinct color but this has not yet been proven.
The lack of a territorial defense by Grey and Fox squirrels is a reflection on how highly adaptable these animals are. These squirrels will eat a wide variety of foods, have plenty of nesting locations (including commercial squirrel houses!) and are smart enough to adapt to just about anything.
These squirrels have excellent memories and can easily find most of the food they have cached so they are not reliant upon a central midden like Red squirrels.