Matt here, and I’ll give you the answer first. Your hamster needs at least 25 cm of bedding, which is about 10 inches, and deeper at one end if the cage can hold it. That’s the PDSA’s number, and it’s the one I’d use for a Syrian or a dwarf.
Plenty of the cages you’ll see at the pet store have a shallow plastic base, so that number surprises people. It surprised me too. Then I read what wild hamsters actually dig, and what happened when researchers gave pet hamsters anywhere from 10 to 80 cm of bedding. Honestly, 10 inches started to look modest.
So here’s the plan. First the wild burrows and the study, then what the welfare groups and one government recommend, which bedding actually holds a tunnel, how many liters you’ll need, and how to clean without flattening all that hard digging.
Quick note before we start. I’m not a vet or a breeder, and HamsterStar is written by a small team that leans on what welfare groups and small-animal vets publish. If your little buddy seems sick, a vet who sees small pets is the right call, not a website.
Wild Syrian Hamsters Dig About Two Feet Down
Syrian hamsters, the golden ones, come from a dry patch of northern Syria and southern Turkey. They’re rare enough out there that the IUCN lists them as endangered. In 1997 and 1999, a team of researchers went looking for wild ones, and they found and mapped 30 burrows. They dug into 23 of them to see how they were built, and the paper came out in the Journal of Zoology in 2001.
Most of the burrows were under farm fields, mostly ones planted with legumes. The layout was simple. One straight drop down from the entrance, then a nest chamber and at least one more chamber for stored food.
And the depth? The shallowest burrow went down 36 cm (about 14 inches). The deepest went 106 cm, which is over 3 feet. The average was 65 cm, so a wild Syrian sleeps a little over 2 feet under the dirt.
One more detail I love. None of the lived-in burrows held more than one adult. That’s your Syrian telling you, straight from the wild, that it wants its own place.
Nobody’s asking you to dig a pit in your living room. But it helps to know what that furball is wired for. When your hamster shoves bedding around at 2 a.m., it isn’t being weird. It’s trying to build a burrow, with a bedroom and a pantry, and it’s working with whatever you gave it.
What 10 cm Versus 80 cm Did in the Lab
The study everybody quotes on this came out in 2006 in Applied Animal Behaviour Science. Hauzenberger and two colleagues (Gebhardt-Henrich and Steiger, if you want to look it up) kept golden hamsters on 10, 40 or 80 cm of bedding and watched what they did.
The 10 cm hamsters chewed the cage wire a lot more than the others. They ran on the wheel more, too.
Every hamster in the 40 and 80 cm groups built a burrow and used it. And in the 80 cm group, the researchers never once saw wire-gnawing.
Their conclusion was plain: deep bedding that’s good for burrowing can be recommended for golden hamsters.
Here’s my read, and it’s just my read. Bar-chewing is the thing most owners notice first, and it’s easy to blame the hamster for it (“he’s just a chewer”). This study points at the setup instead. A new chew toy is nice, but it won’t fix a cage where there’s nothing to dig. And the extra wheel time sounds healthy until you notice it showed up in the same shallow group as the bar-chewing, so I don’t count it as a win.
So How Deep? My Numbers for a Syrian and a Dwarf
The people who write the standards don’t agree on one number. They do all point the same way, though. Down.
Switzerland’s federal food safety and veterinary office, the BLV, says a Syrian’s cage there must have at least 15 cm of bedding, made of wood shavings with hay and straw mixed in. In the same breath it calls 30 to 80 cm ideal, so the hamster can dig its chambers underground.
In the UK, the PDSA says no less than 25 cm, or 10 inches. Over here, PetSmart’s own setup guide calls 6 inches the recommended minimum and says many experienced keepers give 8 to 12 inches in at least part of the cage.
So here’s what I’d do. Make 25 cm (10 inches) across the whole cage your floor. Then pile one end deeper, 40 cm or more, if the walls are tall enough to hold it. That’s the depth where every hamster in the 2006 study dug in.
Dwarf hamsters get the same number from me. I couldn’t find a welfare group that gives a dwarf a smaller one. The PDSA’s 25 cm is written for hamsters, period. A shallower cage for a smaller hamster sounds logical, but I’d give a Roborovski or a winter white the same 10 inches you’d give a Syrian, and let it decide how much of it to use.
One practical catch. The deep end only works if the cage can hold it. The BLV suggests an enclosure about 50 cm tall, and the PDSA’s minimum floor is 100 × 50 cm. If your setup is smaller, our hamster cage size checker will show you how it stacks up against every published minimum.
Bedding That Holds a Tunnel
Depth is half of it. The other half is whether the bedding keeps its shape once your hamster digs in. A tunnel that caves in every night is a tunnel your hamster has to dig again, and again.
Paper-based bedding is the one most guides put first. PetSmart calls it the most widely recommended option, and the PDSA says you can use it on its own or mixed with others. Go unscented.
Aspen and hemp are dust-free, the PDSA says (spruce too), but they aren’t good at holding up burrows by themselves. If you like the look, mix paper in with them. Hamster Society Singapore goes further and calls aspen the only safe wood-based bedding.
Then add hay. The PDSA says soft hay adds structure, the RSPCA lists good-quality hay, shredded paper and cardboard as nesting material, and the Swiss BLV puts hay and straw right in its bedding rule. I think of the hay strands as kinda like rebar. They tie the loose paper together, so the roof of a tunnel stays up.
One trick from a UK rescue, the Bunny Jackpot Foundation, is to press the bedding down gently as you add it, instead of dumping in one fluffy pile. They say packing it helps the burrows hold. It takes a few extra minutes, and it’s worth every penny of the bedding you just bought.
What I’d Leave on the Pet Store Shelf
Some bedding sits right next to the good stuff and still isn’t a good idea. Here’s my skip list, and who says so.
Cedar and pine shavings. PetSmart’s own guide says to avoid them because of their aromatic oils, and Hamster Society Singapore calls both extremely toxic to hamsters. That strong fresh-wood smell when you open the bag? Those are the oils.
Dusty shavings and sawdust. The PDSA says wood shavings and sawdust are very dusty and can cause breathing problems. Fair warning, the RSPCA is softer here and calls dust-free wood shavings a good compromise. Where the experts split, I go with paper and skip the argument.
Cotton wool and fluffy “hamster fluff.” This one’s a hard no. The RSPCA says the thin strands are hard to break, can tangle around a hamster’s limbs and cut off the circulation, and that can end in amputation or euthanasia. The PDSA adds that fluffy bedding can cause life-threatening gut blockages if it’s eaten.
Scented bedding. The PDSA says it can irritate your hamster’s airways. Your nose might like lavender, but your furry friend sleeps in it all day.
Thick toilet paper. The PDSA says plain, cheap, unscented toilet paper works, but the thick kind can cause gut blockages. If your hamster nibbles its bedding a lot, we’ve got a whole piece on whether it’s okay if your hamster eats bedding.
How Much Bedding to Buy
Okay, here’s the part nobody mentions until you’re standing at the register. Deep bedding takes a lot of bedding.
The math is easy. Multiply the floor’s length by its width by the depth, all in centimeters, then divide by 1,000. That gives you liters, which is what most bedding bags list.
Take the PDSA’s minimum floor of 100 × 50 cm. At 15 cm deep you need 75 liters. At the PDSA’s 25 cm it’s 125 liters. Go 40 cm deep across the whole thing and you’re at 200 liters, which is a lot of bags. A half-and-half setup, 40 cm on one side and 15 cm on the other, lands at about 138 liters.
One thing to watch on the label. A lot of paper bedding is sold compressed, and the bag lists how many liters it expands to. Use the expanded number for your math, or you’ll be making a second trip halfway through the fill, which is a total pain on a Saturday.
The good news is you won’t be buying that much every week, as long as you clean the right way.
Cleaning Without Wrecking the Tunnels
Deep bedding changes how you clean. Dump the whole cage every week and you flatten every tunnel your hamster built, and then it starts over.
The RSPCA says to spot clean every few days, taking out soiled bedding, uneaten food and droppings, and that a deep clean once or twice a month is enough in most cases. The PDSA leans more often. It suggests a daily spot clean, a full clean once a week for small cages, and every few weeks for larger set-ups. That’s one more point for the bigger cage.
Two tips from those same groups make a real difference. First, when you do a full clean, put back a handful of the old bedding that’s dry and not soiled, so the cage still smells like home. Second, the RSPCA says to clean while your hamster is awake, not in the middle of the day while it’s sleeping.
And don’t let the bedding get damp or smelly, which the RSPCA spells out too. A damp patch is the first thing to scoop, and you can usually get it without touching the burrows at all.
What the Bedding Is Telling You
Your hamster can’t write you a note, but the cage kinda can. Here’s what I’d look for, and what I’d do about each one.
Bars getting chewed every night? Add depth before you buy anything else. That’s the exact behavior the 2006 study tied to 10 cm of bedding, and at 80 cm the researchers never saw it.
Tunnels caving in? Mix in more paper and some soft hay, and press it down as you go.
A tube sitting on a bare floor is a hiding spot, not a burrow. It’s fine to give your furry friend tubes and hides, but set them on top of a deep layer, so the digging can happen underneath.
And one that has nothing to do with bedding. A wet, dirty bottom or diarrhea is a health problem, not a bedding one, so call a vet who sees small pets the same day. If you want the background, our post on wet tail in hamsters covers it.
If I were setting up a cage for a new Syrian tomorrow, here’s what I’d do. Paper bedding with a few handfuls of soft hay mixed in, pressed down in layers, 25 cm across the whole floor and as deep as the walls allow at one end. Then I’d mostly leave it alone, scoop the dirty spots, and let that little buddy dig.