I recently started planning a new backyard project to build a summer house. Our yard backs onto a wood which is rife with rodents, so my fear was that rats will be squeezing under the door and getting in when we aren’t using it.
Like many people, I’d heard that rats can flatten their bodies and squeeze under doors. How true this is, I wasn’t sure… until I researched it.
Here’s all you need to know how rats squeeze under doors and the truth about them having collapsible skeletons (or not).
Can rats squeeze under doors?
Rats can squeeze under doors providing their ribcage and head fits under the door. Whilst it is possible for rats to stretch their front and back legs out, and contort themselves to squeeze under closed doors, they cannot make themselves totally flat to the floor.
This means that it’s unlikely that big rats can squeeze under doors that have a typically sized gap between the closed door and floor.
However, smaller rats and baby rats could squeeze under doors if the gap is 1 inch (25mm), as this is how thick a rat’s ribcage could be. Some smaller rats can squeeze under doors that have a 20mm.
Given that most doors that go from a property and open out into a backyard won’t have gaps that big, most external doors should be safe from rats squeezing under them.
How do rats squeeze under doors?
Rats go under closed doors by first poking their head and whiskers into the gap. If their head fits, they will wiggle themselves under by making their front legs go flat against their body and stretching their rear legs behind them.
By doing so, rats squeeze under doors and gaps that might otherwise look not possible.
Can rats flatten their bodies?
There’s a widely held belief (or myth) that rats can completely flatten their bodies, which is why many people have the fear of rats squeezing under a door. The truth is rats cannot flatten their bodies.
But they can fit under surprisingly small gaps despite not having a collapsible skeleton as many have been led to believe.
What rats can do though is take advantage of stretching their legs out flat, just like a human might do to get under a small gap. This makes their body into a cylindrical shape, rather than the classic “hunch” physique you often see rats displaying.
Rats can squeeze under doors providing the widest part of their body can fit. For a healthy rat who is not overweight, that aspect if their ribcage.
You might see rats quickly running down a fence line in your backyard, and in a dash and blur, they seemingly disappear very quickly under a gate or door.
The speed at which they do this can make it look like they flattened their body – and they did, but not to the extent that their whole skeleton collapsed.
How do I stop rats getting under my door?
If you have a gap of 1 inch of more under a door, chances are that a rat could squeeze under it when closed. Short of buying a new door to fit more snugly into the frame, there are a few easier things you can do to stop rats getting under.
Here’s a selection of ways to block rats from getting under doors.
1. Door sweep / weather stripping
This one you can buy on Amazon simply sticks on the bottom of the door and covers any gap an opportunistic rat might try to fit under.
2. Attach stainless steel mesh
Rats can chew through weak chicken wire, so make sure you buy a heavy-duty steel mesh which you can then tack to the bottom of the door, covering any gap.
Sheet metal is another thing you can use, as rats cannot chew through it.
3. Block the gap with towels
This is a short-term solution to use before you get a sweep or cover for the gap. It’s not ideal as will prevent you easily come in and out but can deter most opportunistic rats from attempting to get under the door.
If you have a cat flap, consider replacing it with an electronic one, and giving your cat a sensor collar so it’s locked to rodents.
You might also enjoy these answers on backyard rat problems
Can rats climb walls?
Rats can climb walls, but only in specific circumstances. Whilst their paws and claws make them relatively adept climbers, and the tail can be used as a counterweight to help withj balance, they cannot scale smooth surfaces.
The average rat might weigh 300 grams (just over half a pound) so gravity is not on the rodent’s side. This is why most rats will climb walls by using the support of a drainpipe, or similar. Rats will insert themselves in the gap between a drainpipe and a wall as they can push their back into the pipe and climb up easier.
If a rat is going to climb a wall without support, it needs to be a rough surface such as brickwork or pebble dash. They will have to attach and pull themselves up a wall using crevices, bumps, lumps, and tough textures to grip into.
Climbing a wall take a lot of effort for a rat. Unless the rodent knows there’s a rich reward at the top of the wall, or they are escaping a predator, climbing is not something rats are inclined to do.
But that doesn’t mean it won’t happen, and is a fantastic reason why it’s a good idea to plug any small holes in your home’s roof.
Can rats get through air bricks?
The holes in a typical air brick are too small for the average rat to squeeze through. Rats might be able to get into a small hole of 20 to 25 mm wide, the holes in air bricks are far smaller than that.
However, mice have been known to fit through air bricks, so it pays to fit wire mesh over any potential entry point from your backyard into your home.
That doesn’t mean air bricks are not a potential weakness that rats can exploit though. Despite not being able to squeeze through air brick holes, rats have been known to chew through the weak brick in the lattice design.
More backyard guides…
Door photo from https://unsplash.com/photos/XF-5_QY7hDo
