Hamsters can squeeze between cage bars, through a gap in their playpen, or underneath some doors. Once free, hamsters will scurry toward a hiding place, making them difficult to find and remove.
This problem can be prevented with an enclosure without gaps or smaller bar spacing (less than an inch) that a Syrian hamster or dwarf hamster can’t squeeze through.
Hamsters are small and flexible, as most of their body mass is fur. This makes it relatively easy for them to crouch down and get through small openings, even if the gap looks much smaller than the hamster.
How Can Hamsters Squeeze Through Holes?
Hamsters can squeeze through holes because they can flatten their bodies. You may see this even when the hamster isn’t crawling through a tight space, such as when they flatten themselves to cool off.
They developed this ability as a defense mechanism to avoid danger. When predators pursue them, hamsters can escape by flattening themselves and squeezing into tight spaces.
Hamsters and other rodents (like mice and rats) can achieve this due to their unique anatomy.
Human shoulders are connected to their skeletal structure by our bones, such as collarbones, while hamsters’ shoulders are connected to the skeleton by flexible ligaments.
Hamsters have a full range of motion and can flatten themselves enough to crawl through tight spaces.

Can Hamsters Squeeze Through Bars?
Some hamsters can squeeze through bars just 1-2 inches wide. If the hamster’s head (skull) can fit between the bars, the rest of its body can also get through.
Even Syrian hamsters (the largest hamster species) can squeeze through a 1 or 2-inch-wide cage bar opening. If you look at the cage, it may seem impossible for a Syrian to get through the bars, but it isn’t.
Hamsters look fat, but their skeletal structure is smaller than it appears, as most of the body is fur. So, it can escape the cage by squeezing its skeletal structure through the bars.
Hamsters in cages are more likely to escape and get lost than hamsters in solid enclosures.
Instead of a cage with bars, get the hamster a glass tank. You can have a mesh lid at the top for airflow, so the hamster will have great difficulty escaping, provided you secure the lid properly.
If you want a cage, choose a solid construction with narrow bars. Then, monitor the cage’s structure because the bars can warp and bend due to age, weather conditions, and usage.
Can a Hamster Fit Under a Door?
A hamster could fit under a door if the gap is large enough. This could be the case if the door wasn’t the right size, hung correctly, or has gradually worn away over time.
A hamster is more likely to be able to slip under the door if the floor is made of wood or tiles but may struggle with carpeted floors because its body won’t slide along as easily.
If you believe your hamster could fit under the door, you can get a door gap filler. You can slide the filler under the door to cover the gap.
However, hamsters can bite through many things, including foam or plastic door gap fillers.
If the hamster is biting through the good gap fillers, it may be time to get it a playpen instead of letting it roam around the room freely, which is true even if you’ve covered any obvious gaps.

How to Hamster-Proof a Room
The first step is to hamster-proof the room. Even if you get an aquarium tank, the hamster could escape from your hands as you handle it and scurry off into a gap in the wall or skirting boards.
Here are some ways to prevent you from losing a hamster:
- Room type: Choose a room that isn’t cluttered. If the hamster gets lost, you can find it.
- Check the walls for holes: Holes appear near electrical sockets and skirting boards.
- Door gap-fillers: These put a dampener on the hamster’s escape plan.
- Close doors and windows: Ensure there aren’t any electrical wires or bookshelves near the window that a hamster can use to get to the windows and climb out.
- Playpen: Sometimes, hamsters get overwhelmed by the space they find themselves in and feel unsafe, so they find the nearest hole they can squeeze through to feel protected.
What Size Hole Can a Hamster Fit Through?
A hamster can fit through any hole slightly bigger than their skull.
Most of what looks like fat around the hamster’s face is fur. Hamsters’ faces are slimmer, so they can squeeze through a hole much smaller than their face.
If you want to know just how small a hole a hamster can squeeze through, perform an experiment.
Get a thick cardboard box and create a sliding door that is the only exit out of the box. Cut out a circle the hamster can fit through on that sliding door.
Create different doors with holes in decreasing sizes. Place the hamster in the box and coax it into squeezing through the hole. A point will come where the hamster can no longer fit through the hole. Take that limit and decrease it slightly.
However, hamsters can flatten themselves further when they sense danger. Adrenaline can cause prey animals to do things they normally wouldn’t be capable of doing.
If there’s a perceived threat, they’ll do their utmost to escape, which often involves squeezing through gaps that appear impossible for them to escape through.