I have done some limited bat exclusion work so I'm sure not a expert.
So do you think Bats can chew holes to gain exit/entry areas.

No they cannot.

If you look at a bat skull and the tooth structure, you can see that they lack the ability to make their own openings unlike a rodent.

No, BUT if the seal is weak and the instinct is strong......

Bats as a rule are not chewers but I no longer use foam for bats for a reason.

I also thought they did not chew. But have no real basis for that. It appears there are mixed thoughts on this. Has there been any real studies on this that any one knows about.

You can look at the book Bats of America by Roger Barbour & Wayne Davis

Wanted to take a stab at this for you moleman,

Eric and David are both people I consider friends with solid bat experience under the belt that I trust.

I think we have to look at some definitions to clarify your question. Questions in our industry often
lend themselves to plenty of opinions and some of this is certainly due to the way questions might be
posed.

So....

Chew - my definition in wildlife of chewing would be during consumption of food sources, in this case
with bats, insects (leaving out the nectar drinkers in my part of the world).

When clients ask me about bats in their home and the type of damage they often are thinking of bats
as they would mice.

When they think of mice or when I think of mice, rats or other rodents I'm thinking the major gnawing power
they have to go through solid wood and other construction materials even on up to with rats getting through
concrete.

So back to your question, can a bat "chew." With my definition they of course can and all would agree, but
I believe you are wondering mostly about exclusion materials and maybe about home damage, in this case
I would be thinking gnaw would be the word I'm consumed with.

This might seem like semantics but do believe words are only as good as the meaning we put with them.

Do bats gnaw through wood and other construction materials to create roost sites? This is widely documented
to be no. They are considered secondary cavity nesters meaning the cavity or roost site must already exist for
the bats, one reason why existing habitat is so critical to bats and their conservation. Other wildlife who are wood
boring or gnawing (woodpecker, flicker, squirrel, etc...) all create cavities that once abandoned can provide great
nest sites for bats and other wildlife who don't have the physical traits to create their own.

I know that David has witnessed foam that definitely looked like bats chewed it and I don't doubt he saw this for
a second, even though I don't believe that I would call this gnawing versus being a situation that might arise
from a high affinity to a roost site, being excluded and crawling around on the foam trying to gain entry. Thumb
nails on bats as well as the nails on their feet are plenty pointy and those fine tips to me could abrade very easily
the light characteristic of newly cured foam.

If you think about how wood looks when bats have crawled over it for years or decades as many of you have seen
in churches, homes, etc... and I've seen in those and in wooden timber bridges, the wood gets seriously abraded
and on foam I believe this would certainly look and behave like the foam was "gnawed" or "chewed."

***

So now we go to behavior and biology.

Why would a bat chew/gnaw their way through foam or other lightweight materials of a soft nature? One reason
could be maternity colony where adult bats were locked out and pups were inside with foam between. Maternal
instinct is strong in most species as the life investment and biological toll of raising offspring is massive. I've
seen enough jobs where folks foamed in bats at this point even just 3 years into our company that I can state I've
seen foam scratched, roughed up, gouged and picked apart, how it was done, tooth, nails?

I also believe with a major affinity to an old roost site bats might try to get in to the point of tearing out some foam
again, through which mechanical method I don't know.

***

Finally, look at the teeth and this is where we would biologically and morphologically be inclined to agree that bats
were not designed to be gnawing, (chewing) species.

Their teeth are meant to fulfill their role as predators of insects and to be able to use canine teeth to capture the insect
and the rear teeth to macerate those insects for digestion.

All wildlife have teeth that show us a bit about their life history. If someone told me a bobcat was gnawing its way through
the wood framing of their log cabin, I'd have a hard time believing it, even if a bobcat could technically gnaw if properly
motivated, but what is the motivation?

In the end wildlife unlike humans expend calories driven by biological needs and principles. Unless you are living in a third
world country most humans do not abide by these rules. We can acquire food from the store, shelter with money and so on.

Bats and other wildlife must use the calories the expend in the wisest way possible and trying to gnaw through building materials
with their predator adapted tooth structure is a caloric expense without a productive outcome.

***

This is my .25 on the subject, but I guess I'd say that though I know many who hung up their foam, most hung it up due to
the other creatures that will take that foam down in a few moments (squirrels, rats, birds, etc...).

Hope that helps some toward your answer, again I do believe what David saw and I do believe what Eric says as well. Any creature
is capable of things we don't see them regularly do, but those anomalies are not the rule they are generally the exception, ultimately you have to base your exclusion on what you are comfortable with and if squirrels and others are around, it is prudent to not rely on the foam and
other lightweight materials anyway...

Best,

Justin

Yes they do, can, to an extent

Moleman,

Would be good to know exact terms of what you are asking.

Are you asking do bats chew through pur foam?

Or are you asking do bats make a new hole through wood or other home structure the way a squirrel might if blocked out?

More iterations exist, but I'm assuming one of these two are your question..?

This.
Are you asking do bats chew through pur foam?

'are you asking do Bats chew thru Pur Foam'

I experienced that. Now I use brown/white aluminum flashing or put stuff-it then foam. I only use foam on small openings.

They definitely can chew thru fur foam and great stuff foam over a period of time. I have seen it and watched them do it with binoculars from the ground many years ago.

There is no question from my experience they chew very well thru those types of materials. Their roosting sites/maternal sites are high interest areas and preferred sites that are habitual places for them to get to sometimes at all costs. If you havent used integrity materials to repair the primary entries and all secondary points of entry I assure you they will get back in.

Do an exclusion this summer on a structure and have the customer replace their roof with new shingles in the next year or so.In doing this the roofer in many cases tears your primary dormer seal points or ridge vent gap repairs out. Guess what, you will have that colony back at home in short order. Just like having your kids grow up and move out as they grow older. They always know where home is located and come back for one reason or another.

They can chew through fiberglass screen too...

This just in pur foam stock prices plummet....

Foam has its uses and certainly has its place for its use in our industry. However one must understand its limitations and know the creatures capabilities that you are attempting to exclude with such a product. Understanding this keeps us grounded to understanding its limitations and learn where it is a good product to use with good judgement.

Backing foam with wire or caulk has always been a good thing in my mind when doing bat exclusions but i didn't do it because i thought bats could gnaw/chew.
Some different thoughts on this subject for sure.
Thanks every one.

Aside from the chewing issue if one has seen as many "foam exclusions" as I have you understand why I deep sixed the todal years ago.

I didn't want to have to deal with it so I threw the foam guns away and made my guys and myself use other products. Besides Solar Seal and Cobra Vent look much better.

Out of those who have "seen" bats "chew" foam, how many have witnessed this as Bob says with binoculars and how many
evaluate the following year or when a call back or warranty inspection happens and see simply the foam is gnawed, chewed
or gone and the bats were back and so they were the cleanest decision tree end for "who dunnit" so to speak?

I'm seriously curious, I do use foam along with the other products available to us to assure exclusion, I've had pack rats (wood rats)
lay waste to it in my first year on a couple of ranches where I was ignorant to them going to the locations I thought were safe, however
the rest of my exclusions haven't witnessed this damage to foam.

Here in the desert I have about 4-6 species that we routinely exclude including the typical species for other parts of the country like big
brown, Mexican free-tailed bat and little brown along with some other myotis and Pallids.

I'm sure you guys have seen where someone (homeowner or otherwise) foamed in bats that were trapped live in the wall, I've witnessed this
more than I care to say out here and in none of these cases were the bats making any headway on trying to leave through the foam which was
a life and death scenario.

***

For the record I am truly interested in this topic, we all know that any building material can be compromised by the right animal in the right scenario, what I'm interested in are the following questions related to this topic.

1) If you stopped using foam because of bat damage to this product and re-entry into structures that you excluded did you....

a.) see the bats do the chewing/gnawing?

b.) see the evidence and since the location was an entry point assumed bats as culprits?

c.) see evidence and bats were back and thus again connection was made?

2) Which species of bat did you see do this, or have you seen multiple species do this and if so which species if identification was possible?

3) What time of year was this, summer time when maternity season was imminent, or various times of year from spring to fall?

For now thats likely enough questions to muddle this a bit, but hopefully you see I'm interested truly in knowing some of these variables and surely no excluder that works with bats wouldn't want to have the advantage of some of these bits of wisdom or sightings folks might have.

*****

Oh, one last thing, everyone is talking foam right? Not that bats are chewing into a home through wood and other structural components that would require rodent teeth or raccoon tenacity?

Just wanting to clarify as the topic of the thread is simply "can a bat chew" not can a bat chew foam?

Thanks, oh and Bob, I definitely agree every material has its place and learning that is one of the most important things we do with wildlife exclusion, wasn't poking fun at anyone with the "stock prices drop on pur foam" was an overall statement related to everyone piping up saying
foam for bats is fallible in general, expect a lot of guys to stop ordering it or doing entire exclusions with it alone as we all know so many who do.

Best,

Justin

I have not witnessed it first hand as Bob did. I have had damage to foam as you described in an earlier post on several call backs. Nails, claws or teeth unknown but the normal smooth surface of cured foam was abraded down to the rough interior and in some case worn enough for reentry. Just a note, anyone who has never had a bat exclusion failure is either a liar or a wet behind the ears rookie. One notable was a chimney top, brick wrapped wood chase with metal pan cap, that had reentry not once but twice in the exact same spot which was the exact location of the primary bat entrance. Yes, I'm a slow learner. The conclusion ruled against flying squirrels as the opening was linear over a six inch area as opposed to the usual perfect round flier entry. This was also the job that fired my foam gun. These bats were lecontes freetails (note, I am now using the proper subspecies designation for our southeastern freetails) but most of the others were big browns though personally I think freetails are more likely to be an issue for reentry.
It's hard to gauge the difference between the two as I do twenty big browns to every one free tail but the free tail colonies tend to be larger and in more difficult presentations due to their colony size and site preferences. So is a freetail jobs likelihood of re-entry a factor of site fidelity or a combination of colony size and condition of site? I'm still trying to figure it out. BTW, I never see little browns.

In my experience, Bats, probably little browns, I don't identify, definitely were the culprits. I check for rodents including squirrels on every Bat job. Rodents make a clean rounded opening. When Bats make an opening it is jagged. Again in my experience. I have been doing Bats for ten years. I have a warranty job where I didn't back up my foam. I'll be getting there soon. This will be maybe the third time I have had this happen. I do 10 plus Bat jobs a year. I'm not a liar, LOL.