Stephen Vantassel is going to talk today about. House mice. A lot of you are probably dealing with house mice But maybe you’re having situations where you’re just not getting the level of control that you want. And my suspicion is a part of this is due to the fact that we don’t have a full appreciation of all of the aspects and abilities capable of house mice. House mice are amazing creatures. And so what I found when I give presentations is that a lot of people don’t really know or don’t really fully appreciate how much physical abilities. Mouse actually have.
Getting Reacquainted With What House Mice Can Do
So I wanted to give you a little bit of data here. Maybe some of this will be a refresher for those of you but if that’s the case it’s never hurts to read get reacquainted with what this mouse can do as well as for those of you don’t know. And this will be a good start for you to understand what the mice can do and often what it can’t do.
First let’s talk about climbing abilities they are exceptional climbers essentially they can climb up any rough surface. So a lot of times and buildings that have brick exteriors mice are just going to climb the brick and then where the boards that usually at the top near the soft area of overlaying the break. You’ll notice that a little gap those gaps caused by the mortar joint. That that does use to see you put two bricks together but there’s usually a gap there because it’s usually indented in and the board doesn’t fill that gap. So a mouse just has to climb the brick squeeze right underneath that board and voila it’s inside the attic and has its run of the home. In that situation a commonly overlooked way for mice to get in.
I had a lady from Colorado once give me a ring and said she had a brand new house. And she said she had mice and called an exterminator the exterminator came out and did exclusion along the foundation and I said Well didn’t they tell you that mice climb. And she her answer was mice climb. And the answer was Absolutely because the exclusion around foundation was definitely important definitely helped her. But she still had mouse problems. Why. Because mice climb. Don’t forget that if you’re going to do a true mouse exclusion and yes, it is possible.
It Is Possible To Do Mouse Exclusion
It is possible if we repeat that it is possible to do a full mouse exclusion on the structure. Didn’t say it was easy. Just telling you it’s possible it can be done. You need to go from the peak of the roof all the way to the ground. So that’s how you got to look at that. So mice can climb any rough surface. Second what can we call it rope climbing. But they can climb a 10 gauge wire. So that’s a wire. That’s the theory the thinnest wire they’re going to be able to climb. How good are they at swimming well unlike the Norway rat the mouse mouth is a very poor swimmer.
So you’ve probably heard many of the stories where people have created little ramps over buckets full of water and they put some peanut butter on it and when the mouse gets on it the mouse falls off and falls into the water in the course and he’s swimming for a while and can’t and can’t get back out because he drowns. So they are very poor poor swimmers were rats on the other hand are rather good swimmers for themselves.
How small of an entry can a mouse get into. Well the minimum width. And again we’re focusing here on the skull of this mouse. They know that some people may have the misguided notion that mice can readjust their bones or they’re flexible on all that. And I say that the hole is going to be determined by the size of the head. They’re not going to be able to shrink their head. So the research shows down to about a quarter of an inch so point two for inches which would be about a quarter of an inch is a great rule of thumb if you’re going to try to secure something out against house mice quarter inch.
Well hardware cloth quarter inch mesh is going to pretty much do the job. So down to point to four that’s good it really do it. That’s going to be a minimum such a good rule of thumb for you to use.
Mouse Have Amazing Physical Abilities
How far can they do a running jump. So if they’re trying to jump across something how far can they go in the answers about 24 inches. Think about that for an animal that’s only about six inches long tail tip of the tail to the tip of the nose that’s an adult is about six inches long that they can jump literally four. Times their total length. And if you’re just looking at body length you’re probably looking at something closer to eight times there. So it’s an enormous ability. Think about the springboard action of that. So we need to appreciate that gaps that sometimes like how are mice getting onto the countertops and things of this nature. They are exceptional climbers and they’re exceptional sleepers. Now here’s the other piece of evidence that I think a lot of people don’t appreciate and this was some research done out of Hawaii.
The research was done by a gentleman called me get his name out here. His name is William S. Pitt and he published and his co-authors published an article. That said physical and behavioral abilities of mental rodents related to the design the selective rodent side bait stations of the traditional journal of Pest Management volume fifty seven. Point three which is the third edition 2011 pages one eighty nine to one ninety three.
Let me kind of summarize some of his work there what they did is they wanted to find out how high could a mouse jump in a vertical leap. Now understand what this is going to be describing. It’s a leap from one horizontal surface straight up to a second horizontal surface or what they did was they took off right. Like 20 different mice different ages some some were young some were older and they basically took platforms and they taught the mice to keep jumping to these levels by using bait and getting them to make these leaps. These are not running jumps. We’ve already talked about that ability. These are vertical leaps. This is sort of the Michael Jordan just leaping up dunking the basketball right. So this is what these mice were doing they’re jumping from one surface to the next surface. Here’s the information I want you to take home to the weakest mouse
The third person on the basket. You know the third string of the basketball bench. These were not your best jumpers. These are not your best players. The weakest mouse jumped nine point eight inches.
Think about that. Almost 10 vertical inches. Now if the weakest mouse can jump almost 10 inches vertical. What do you think the Michael Jordan mouse could do. The mouse that has really exceptional jumping ability.
I’m showing my age here Michael Jordan was just an amazing basketball player and he he could do some do some jumps toward do some dunks from amazing distances he had incredible physical ability and so this is the kind of analogy I’m using. What do you think the best mouse can do. So if you’re wondering why you know you have mouse droppings sometimes on on shelves and places like that how did the mouse get up here. Well I want you to be thinking about can the mouse climb up there. Probably but if not they’re going to use situations with mouse just jumped you just jumped up to that particular level. And that’s an exceptional abilities. Once you think about that the rule of thumb is think about 10 inches that mouse. Can Jump up. So understand the physical abilities of these mice that you’re going to have to keep this in mind when you’re doing your inspections. You’re trying to understand mouse behavior don’t ignore areas with a goal that’s to finally do go into there because the mouse probably can reach it. Probably not. Probably the mouse could get into that area and we need to have a better appreciation for what mice can do.
Mice Have Amazing Reproductive Abilities
So let me give another issue about mouse reproductive rate and sometimes you’ll see some statistics that go out there you know mice can you know repeat of several months you get all you don’t get hundreds of thousands of mice some obviously being a little superfluous here and a little facetious but you’ve seen some amazing numbers have been in somehow mice able to reproduce. Well. Those are often governed by ideal circumstances where food and shelter are not an issue. Obviously mice have high reproductive rates but those reproductive rates are governed by the availability of food in the availability of space. And so this is something that we have to think about and that is what happens is sometimes when we come into a situation and try to control mice you know we’re feeling like rock stars we’re trapped in mice or poisoning mice and the customer is getting happy and we think we’re done and we remove the remove the materials that we use to control those mice and then three months later we’re getting a call saying they still have mice. What happened. Well what likely happened was is that you reduced the mouse population from a high level to a low level but you didn’t eliminate the mice.
And so what happened was there was enough mice there available that in a few months they were able to exploit the food that it was available and were still able to some of that female that all important female was able to then reproduce and then create other young and B and they had a little bit of an explosion. Why. Because she’s got plenty of food available. A lot of times clients aren’t going to be removing food sources available. It’s going to be plenty of shelter because you’ve already freed up a lot of places for the mouse to be because you’ve killed their relatives or earlier members of that particular house.
And so then they have that ability to have maximum families. But let me give you sort of some minimum numbers I’ve used conservative numbers on this just so we get a reflection about an understanding of just how well mice can reproduce. So let’s consider two mice a male and a female. So they mate the female gives birth within three weeks about twenty one days three weeks we’re going to say that she’s had five young which is on the lower end of their normal reproductive rate and we’re going to say three of those young are gonna be males and two of those young are going to be females. All right. So now that we have three weeks we have our so first batch of young. In those in 56 days. Those young are going to be able to mate and those two females are then going to be able to reproduce. Number you can trap three or two of the males. And you’re still good to go because there’s going to be two males laughter even have one male and one male can take care of all all the females.
No problem. Remember when we’re doing mouse control it’s all about the females. Now I’ll give you a little bit of another statistic here.
Information in the moment here but stay with me. So we have three weeks for the first batch of young. It takes 56 days for those young to mature enough to be able to mate. So now we’re up to about 90 excuse me seventy seven days.
Little over two months. Seventy seven days. So we’ve got two months plus about two weeks so we’re out we’re not out about eight weeks then they mate and 21 days later they could have young and I’m using conservative numbers here and we’re now going to have a total of 10 young. So now if you consider that the adults are still going to be alive we’re going to have a total of seven plus 10.
We’re going to have a total of 17 mice within the space of about three excuse me about four months.
We’re going to have we go from two mice to 17 mice in about 19 and about four four months. Think about that. You may say well that’s not very fast. Yes but then the next four months those 17 are going to become the we’re going to have a multiplier effect. Now there’s going to be probably some mortality in that. So but again you get this idea of a massive reproductive growth. Reproductive numbers occur when the young when the mice have plenty of food and plenty of shelter.
If they don’t have that then they’re probably just going to go into replacement mode or they have to disperse. So this is why I tell people if you start seeing mice in the living space of an area. Rather than just hearing them in the halls. To my mind a good sign is when mice are spilling over into the living space of the house. That’s a sign that they’ve run out of room in the walls and they’re now getting even worse. So let’s. It’s not always true there are going to be exceptions to this but that is something to keep in mind if people are saying yeah we’ve seen mice in the living space. That’s a bad sign.
Usually the infestation has been there for a while. So let’s talk a little bit about about some control when we’re dealing with when we’re dealing with my side remember I talked about the.
You could have one male take care of all those females and that’s certainly true. But there’s something about males that you want to make sure you understand. Mice when they reproduce the females generally have one to one ratio that is they have for every female they have as a as a child they’ll have a male so they tend to be one to one in their proportions
When you’re trapping if you’re not checking the gender of the mice that you’re catching make sure you’re wearing your PPE your gloves. Right. Don’t get down and dirty with your bare hands here. You want to make sure you’re wearing your appropriate gloves but when you’re checking those the genders of the animals that you’re trapping if you’re catching too many males you’re not getting appropriate control. Sometimes what happens when your trap captures a dominant male. Subordinate males are interested in those traps. They will then go and get caught in that trap because they’re interested. The research seems to suggest that females tend to avoid sense when they smell the scent of a dominant male. They avoid those trap she may feel like a rock star. I’m catching all these mice and you you are. That’s good. But are you catching the right proportion of male and female. If you’re not then you need to make an adjustment. And this all happens as some of those people feel they got great success and they’re not in they are having success but catching males. They’re not removing the infestation they’re what I call their harvesting. They’re not controlling. So what’s the easiest solution for that. Add more traps add fresh clean traps to catch your females and so then make sure that your proportioned. So if you’re off by 10 percent. Not a big deal. So if you’re catching 10 10 males and then 11 females or 11 males and 10 females that’s fine. There’s gonna be a little variation there. But if you’re catch and 15 males. And only eight females you’ve got a problem.
There’s more there’s more to go. That’s something to think about. Well we have a lot more to talk about in terms of when it comes to commencing rodents. In this case house mice. But I hope that will help you get these situations resolved about house mice. Helpful.