Let’s Talk About Bats

Bats.. what do we know about them? Are they protected? Where do they come from? How do you know if you have bats in your home?

When it comes to Washington State, there are around 15 species of bats that are common. When dealing with nuisance wildlife, though, the Little Brown Bat (myotis lucifugus) and the Big Brown Bat (eptesicus fuscus) come to mind. These species are, of course, brown as their description lets on.

Their mating season occurs in the fall, BEFORE hibernation and after mating, the males’ sperm remains in the females’ reproductive tract until spring time when they awaken from hibernation and fertilization takes place. This process is called “delayed fertilization” for obvious reasons. Bats generally give birth to one or two young in May/June, but don’t usually start having young until they are two years of age.  They raise their young in a group of breeding female bats, called a “nursery or maternity roost” in the summer time. Shared body heat is most beneficial for the growth of their young, and they begin to have the ability to fly at 3 weeks of age.

(Fact: Bats can live up to 30 years!)

People usually begin to notice signs of bats in the spring or early summer time. Signs include rub marks at the entry points, piles of droppings (called guano) below roosting sites, urine stains on walls/ceilings, flapping sounds inside wall cavities or inside attic spaces, and clicking/squeaking noises at dusk when they wake up. They love to find small openings (as small as a dime coin) in eaves, chimneys, soffit vents, ridge vents and fascia boards. Their droppings look like those of a mouse, though bat droppings are accumulated in piles, unlike rodents, and they have a very distinctive odor.

Bats migrate twice in a year; once in the beginning of spring and again at the end of summer. Cold temperatures , and lack of available food sources, are the forces behind their migratory patterns to warmer climates or hibernation sites. They take up residence in caves, mine shafts, attics, cliffs, rock crevices, trees, and the occasional wood pile. In cold summer weather, bats can even go into a state of torpor. This consistes of reduced activity and metabolism from lowering body temperatures and is considered to be a brief hibernation. During this torpor state, their first line of defense against danger or threats is to bare their teeth and squeak or hiss loudly to scare the danger away until they can warm up enough to fly.

When dealing with bats. the most common diseases associate with them is rabies. Last year (2017) in Washington state 22 bats that were tested, out of 376 total, came back positive for rabies; Most of which were found in King County. This year it looks as though rabies is being found once again and there has even been one report of a rabid bat biting a college student. We never recommend trying to touch or move a bat that has fallen or roosting inside a home.

For more information on bats and how to go about getting them removed or prevent them from coming in please go to our website seattle.crittercontrol.com OR call us at 1 (800) CRITTER


Critter Control of Seattle










Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s