The Eastern Gray Squirrel is a very common structural
pest. They will frequently chew their way into attics or exterior wall
voids to create nests. Because they are large their presence is generally
quite noticeable to homeowners. They are kind of cute, easily tamed with
food and many people tolerate them even when 
they
know they are living in their attics.
Aside from the damage to insulation and building exteriors there is one really good reason to remove squirrels (and all other rodents) from your home. Fire. Rodents including squirrels frequently strip the insulation off of electrical wire and create the very real danger of electrical fire. The squirrel below simply zapped himself. These homeowners were lucky. It is not uncommon to find electrical wire in attics with large pieces of its insulation completely stripped off.
If you are living with squirrels you really ought to have us out to look at your situation..
