Aggressive Hamster

[Cecioriente]

Hey everyone! I am new to this page. I have had my Male Syrian Hamster(named beatus) since February of this year(2024). I previously had a Female Dwarf Hamster who had unfortunately passed away. Beatus was extremely friendly, energetic and obviously curious when we first got him. We have him the few days to settle and get used to his new home, we noticed he wasn’t too fond of the set up over time(it was a double tiered cage) and only liked the bottom, so we removed the flooring on the top. He was so much happier and was more playful. I handled him whenever he showed interest we clean the cage regularly keep up with food and water. But recently he has become SUPER aggressive out of nowhere. We have no new pets. We occasionally will move some stuff or add new things to the cage to keep things playful and fun but it’s not a crazy change. We handled him regularly. The other day I went to go add new food for him. We are on a schedule with him, I wake up later in the day as I work nights and once I notice him up and roaming I will add food and change his water. This is everyday. He’s normally awake about 2-3hours during the day then active all night. So when he’s up during the day I will add food and water, give him treats, handle him and once a week clean his cage. When I went to add new food and change his water(he was indeed awake) he had no issue with me being around the cage, showed no signs of stress or anything but still lunged and attempted to bite me all while screeching. I still gave him the food but left him. Anytime I go near the cage, or attempt to give him food he becomes aggressive with me and even my boyfriend. I have no idea what to do. He won’t even allow me to pet him, I normally clean his cage on Saturdays and as that’s approaching I have no idea how to go about it. It has been hot where we live but we keep a fan near him(not blowing directly on his cage or him) but enough to keep that area cool, I also place frozen bottles of water near his cage during the day(when the fan is off) to keep it cool as the room gets very hot and i don’t want him to overheat. Nothing in the schedule has changed, we add new toys and items, even snacks to his cage during cleaning, we sometimes arrange where we put his wheel or his hides to keep him stimulated and not so bored, but we never change his main hide or his food bowl or water. He has a total of 3 hides. His two main ones we keep in the same spot since he uses them frequently and he has favored them, we will move his third one around and his toys/chews but never his food water or main hides. I do not know where this aggression came from and it’s gotten to the point where I can barely feed him without being bitten. And when he bites its hard. He will latch onto my hand for a good 30 seconds.

 

[Maz]

Hello and welcome. He is being territorial because they find cleanouts very stressful and feel you're an invader probably. There's an article about cage cleaning tips on the home page - I'll link it below. Weekly clean outs aren't necessary providing he has enough bedding and a large enough cage - it stays quite clean and dry with enough bedding (and a hamster litter tray as most will use one if you put it in their chosen pee spot). If they use the litter tray you just need to empty that every few days.

It sounds like normal behaviour when they feel threatened and invaded. Hamsters really do like stability and things staying the same, so changing things around and removing things will add to his stress as well.

The good news is - they can quickly forget and go back to being friendly and happy again - if we let them have their normal behaviours

Which cage do you have? Does it allow for 8" of bedding? (Or at least 6"?)

Anyway have a read of this first. It's a learning curve getting your head round the idea that they don't need weekly clean outs. Also which country are you in (I'm guessing not Uk as it's not hot here right now!). It can help to know to suggest things that are available that could help.

For now I would leave things as they are in his cage and don't do any cleaning out for two weeks - except to "spot clean" any pee area after a week maybe. To give him chance to settle and scent mark everything again and make it his own. I'd also avoid trying to hand feed him in the cage.

After a couple of weeks maybe get him out of the cage a couple of times a week (if he's willing to walk into a tube) for some out of cage time in a safe area (Eg playpen or sectioned off part of the room). They behave very differently out of the cage than in it as they're only really territorial in the cage.

I'd go back to just talking to him gently meanwhile through the cage.

Hamster cage cleaning

Tips on how to clean your hamster cage and avoid causing stress to your hamster. It's best to have plenty of depth of substrate and mainly spot clean your hamster cage. Avoid disturbing your hamster's nest and hoard.

www.thehamsterforum.com

 

[Maz]

Just to add, biting can also be caused if the hamster is in pain, but I suspect it's not that and it's the clean outs. He has cage rage.

 

[Socks' Mum]

How old is your little cage fighter? Is he definitely male? If you have a preggie female, there might be something amiss, but if he is a mature male his gender should be easy to tell.

 

[Cecioriente]

How old is your little cage fighter? Is he definitely male? If you have a preggie female, there might be something amiss, but if he is a mature male his gender should be easy to tell.

He is 100% a male lol. At first we were questioning, we did get him from petsmart unfortunately, they did say he was a younger hamster when we got him and would grow to be much bigger. he indeed did grow a lot and we recently have noticed some other things and he is indeed a Male.

Hello and welcome. He is being territorial because they find cleanouts very stressful and feel you're an invader probably. There's an article about cage cleaning tips on the home page - I'll link it below. Weekly clean outs aren't necessary providing he has enough bedding and a large enough cage - it stays quite clean and dry with enough bedding (and a hamster litter tray as most will use one if you put it in their chosen pee spot). If they use the litter tray you just need to empty that every few days.

It sounds like normal behaviour when they feel threatened and invaded. Hamsters really do like stability and things staying the same, so changing things around and removing things will add to his stress as well.

The good news is - they can quickly forget and go back to being friendly and happy again - if we let them have their normal behaviours

Which cage do you have? Does it allow for 8" of bedding? (Or at least 6"?)

Anyway have a read of this first. It's a learning curve getting your head round the idea that they don't need weekly clean outs. Also which country are you in (I'm guessing not Uk as it's not hot here right now!). It can help to know to suggest things that are available that could help.

For now I would leave things as they are in his cage and don't do any cleaning out for two weeks - except to "spot clean" any pee area after a week maybe. To give him chance to settle and scent mark everything again and make it his own. I'd also avoid trying to hand feed him in the cage.

After a couple of weeks maybe get him out of the cage a couple of times a week (if he's willing to walk into a tube) for some out of cage time in a safe area (Eg playpen or sectioned off part of the room). They behave very differently out of the cage than in it as they're only really territorial in the cage.

I'd go back to just talking to him gently meanwhile through the cage.

Hamster cage cleaning

Tips on how to clean your hamster cage and avoid causing stress to your hamster. It's best to have plenty of depth of substrate and mainly spot clean your hamster cage. Avoid disturbing your hamster's nest and hoard.

www.thehamsterforum.com

We don’t change out or move thing super crazily and everything is normally in the same spot or about the same spot, either way he ends up moving it all to the EXACT position he wants them. Sometimes he flips it upside down, sometimes he turns it. His cage is a 23.6Lx14.4Wx11.8H(all inches) and his bedding area is about 5.5-6inches tall. He still has his initial cage that I had purchased with my last hamster. I felt bad keeping my dwarf in the petsmart beginner hamster cage so I upgraded and the dwarf had a mansion basically. I did some research and they said that sized cage was big enough for a younger syrian but as they grow they would need a bigger cage, unfortunately I haven’t found a cage I felt would fit him well, I honestly want to make a custom cage and would like to also have it all be plastic or glass as he is big on burrowing(which he does have plenty of space) but he also enjoys climbing and I want him to have some climbing areas and more than enough space to burrow. Since this cage is very small and he was super friendly he would come out and run around the room with us all the time, his wheel is not in his cage anymore, he never used it and we recently took it out about a month ago, and everytime it would be tipped over, buried under his bedding or he would fill the wheel itself with bedding. Once we noticed he never used it(again I work nights so I get home at like 12:30-1:00 and am up until 5:00 then don’t wake up until 11:30-12:00 IL,USA time) so I was also up a lot of the time when he was and if I wasn’t awake my boyfriend was. We slowly incorporated a new hide for him, and once he showed no interest in using his wheel has a hide anymore we completely took it out. When we set up his area for play time outside of the cage we set up his wheel, more chews and toys and a few things from his cage so he doesn’t get stressed. Also I would clean his cage less often and more like every two weeks but I simply feel HORRIBLE about that because for some reason my hamster poops like no other. 3 days after I clean his cage his litter area has not only been cleaned out once or twice a day, but he also still has poop bits ALL OVER his cage. and I simply cannot stand allowing him to be in that sort of filth. I always keep some of the old bedding in his cage especially around his hides. so it has a familiar sent. One of his hides is a peanut shape and isn’t able to be washed thoroughly bc of its material(it’s a chew safe because petsmart did let us know he is a chewer and he is his chews barely last him a week). So that hide automatically has his scent all over it. For the toys and chews we only change them when they clearly have too much wear and tear on them. His toys are hamster safe, for chews I gave given him the traditional wood based chews(with no coloring) I have gotten him some grey blocks(Wanbo 1.6 inch pet chew stones) they are great for keep their teeth short so they don’t overgrown and curve in, He LOVES them and we can always hear him playing with it. I have also given him the apple wood sticks which he loves. I have gotten him the Hay chew blocks(he didn’t show much interest so I don’t give them to him as often, At cleaning I normally fill 2 bowls, one with food(which I fill everyday but i clean it out with water let it dry then refill it) and another with snacks. The hay chew blocks if you haven’t seen them are literally just formed hay with dried flowers, seeds or even fruits in the middle. I have done the Crunch sticks that hang from the cage(which he loves) for toys I have done anything that is hamster safe if they chew it, so mostly hay or wood based toys(again no dye) so the hay balls, a lot of the changing toys which he loves bc he will actually climb on them lol. I mean you name it I have probably used it. A lot of his toys have been removed already because they were just so worn he stopped using them but I do a refresh tomorrow. I just do not know what to do about the cage rage/aggression. It came out literally overnight. The previous day we were playing with him, holding him, we had friends over(which he’s known and loved since we got him) and they held him but thats nothing new. we have the same friends over almost everyday and they will play with him/hold him, even just sit down and let him run around or sit on them. Occasionally we would get a few nibbles like if he still had a small amount of food in the bowl and we removed the bowl to give him more he would nibble at our hand. They only time he feed him from our hand is if he is having lettuce because he will not eat lettuce unless its from our hand(idk why) but he also devours the lettuce. When he is with our friends he is always supervised by me or my boyfriend and if we notice them being rough or attempting to do something he does not like, we instantly take him back and will either keep him out but only allow us with him and they can watch or we put him back in the cage and simply say “that was not okay, he does not like that and that will break his trust/feel of safety not only towards us but towards you, he’s staying in the cage the rest of this time”. This hamster is honestly so spoiled, so well taken care of, he is literally our child. But if this aggression continues to progress I genuinely do not think I can keep him because as much as I love him, and I do. I cannot properly take care of him under these conditions.
As I said even feeding him he freaks out and attempts to bite not nibble bite and will screech at me. As I said the clean is never something super crazy, weekly I will change out most of his bedding but I keep some of the older stuff in near his hides and food. I will clean his water bottle, food bowl, and some of his hides. Once a month I do a complete reset(which is tomorrow but I will probably do it today as we are out most of the day tomorrow, my hamster will still get his out of cage time we live with my boyfriends mom and she absolutely ADORES Beatus and loves his time with her) We were away at the beginning of the week shortly after the aggression started so I gave her a heads up for when she gave him food or went to play with him that he may try to bite her and scream and that I was doing research to find out why. She said she had no issues at all and he was friendly like normal so we are starting to think it is just with us. It’s rare we go out of town for more than maybe one night and even that is rare, if we are gone for more than one night we get an air bnb that is okay with pets being there, double check a hamster(in a cage) is fine and we bring him with, when we are there he normally doesn’t get his out of cage time solely because it’s not my house. So he stays in his cage or if he does go out he stays in our hands/lap. It never seemed to bother him, the first day he would just be curious and looking around like “hey this is a different room” but never changed behaviors. This time we did not bring him since he was showing aggression I didn’t want to change his environment either. It just breaks my heart that he is acting this way.

 

[Maz]

Ok. They do need their wheels to burn off energy or stress can build up. If he had stopped using it, maybe it was too small? Syrians need an 11" or 12" wheel. I also think maybe his cage is too small for him as well, and that's a common cause of cage rage. Especially as they get to be a few months old and their hormones kick in. It's only about 360 square inches, and the recommended size for Syrians now is about 800 square inches. It used to be 650 square inches and 650 would be a bare minimum. The only barred cage that's about 650 square inches is the Prevue cage (also called the Zanzibar cage at Exotic Nutrition) but really he needs something bigger than that.

Most people in the Us get a glass tank - minimum would be a 40 gallon breeder - which is about 36" x 18" but a much better size is a 75 gallon tank.

There are enclosures like the Nitenagel bigger world or vista but they are very expensive. I think petsmart does a dollar per gallon sale when it can be much cheaper to get a glass tank.

The other thing about the size and amount of space is there is more bedding which is why the poops don't really build up and it needs cleaning out less.

You really don't want to worry about poops though - they're not really dirty or smelly or unhygienic and sometimes they actually eat them or keep a hoard of poops - which is normal. They can redigest vitamins and nutrients from their poops. So if you take them all away you're robbing him of his emergency food store . I tend to just pick them out now and then if they start taking over a bit. The only unhygienic thing is their urine.

Also if their nesting material and hoard are thrown away at cleaning time they can get really upset and stressed and anxious as well. Hoards are fine left as long as they haven't been pee'd on and if it builds up a bit you can prune out the bottom half of it (ie the older food). Dried food lasts quite well. And any fresh food they usually eat straight away.

So I think to start with maybe looking at getting him a larger cage and wheel. It does cost more in bedding initially, having a larger cage. But after that you don't need to replace all the bedding. Most of it will stay clean and dry and you can just spot clean the pee. I actually go about 4 to 6 months before changing the substrate - with a 40" cage and 8" of bedding. And even then I don't do the whole cage in one go.

Most of us do partial cleans - eg do a third of the bedding. Then a few weeks later do another third. In kind of segments. So 2/3 of the cage is undisturbed and still smells familiar.

I think he sounds very much ready for an upgrade

 

[Cecioriente]

Ok. They do need their wheels to burn off energy or stress can build up. If he had stopped using it, maybe it was too small? Syrians need an 11" or 12" wheel. I also think maybe his cage is too small for him as well, and that's a common cause of cage rage. Especially as they get to be a few months old and their hormones kick in. It's only about 360 square inches, and the recommended size for Syrians now is about 800 square inches. It used to be 650 square inches and 650 would be a bare minimum. The only barred cage that's about 650 square inches is the Prevue cage (also called the Zanzibar cage at Exotic Nutrition) but really he needs something bigger than that.

Most people in the Us get a glass tank - minimum would be a 40 gallon breeder - which is about 36" x 18" but a much better size is a 75 gallon tank.

There are enclosures like the Nitenagel bigger world or vista but they are very expensive. I think petsmart does a dollar per gallon sale when it can be much cheaper to get a glass tank.

The other thing about the size and amount of space is there is more bedding which is why the poops don't really build up and it needs cleaning out less.

You really don't want to worry about poops though - they're not really dirty or smelly or unhygienic and sometimes they actually eat them or keep a hoard of poops - which is normal. They can redigest vitamins and nutrients from their poops. So if you take them all away you're robbing him of his emergency food store . I tend to just pick them out now and then if they start taking over a bit. The only unhygienic thing is their urine.

Also if their nesting material and hoard are thrown away at cleaning time they can get really upset and stressed and anxious as well. Hoards are fine left as long as they haven't been pee'd on and if it builds up a bit you can prune out the bottom half of it (ie the older food). Dried food lasts quite well. And any fresh food they usually eat straight away.

So I think to start with maybe looking at getting him a larger cage and wheel. It does cost more in bedding initially, having a larger cage. But after that you don't need to replace all the bedding. Most of it will stay clean and dry and you can just spot clean the pee. I actually go about 4 to 6 months before changing the substrate - with a 40" cage and 8" of bedding. And even then I don't do the whole cage in one go.

Most of us do partial cleans - eg do a third of the bedding. Then a few weeks later do another third. In kind of segments. So 2/3 of the cage is undisturbed and still smells familiar.

I think he sounds very much ready for an upgrade

I agree, I am only 19 and finally starting to be more independent, I have a whole savings account dedicated to saving up for a MUCH larger cage. As I mentioned I know he has grown out of the cage so I do a lot more free roam time, his wheel is 11”. I had a much smaller one as before this I had a dwarf hamster. But before I got Beatus(my syrian) I had upgrades whatever I could afford to, so the wheel, the ball, the water bottle and even food because I read Syrian hamsters tend to prefer different foods and need different foods for their nutrition. I just simply cannot afford to get a different cage/enclosure at this very moment. On my days off if Beatus is awake he would normally be out with me. I make sure I take clothes and cords or any small, unsafe items off the floor. I also have a playpen as I babysit a lot so I will even just take him out along with some of his bedding and put his bedding in 1/4 of the playpen and let him roam around in there if I am busy cleaning or doing some work. I have been saving up for a 40 gallon tank and other items to make it customizable so he can have all the things. When I first got him I did read that this sized cage would be big enough for him as he was still young. I try to maximize the space by giving him more bedding so he can have more burrowing areas but he is only really in there if we are gone for the day or he is sleeping. Other than that he free roams. He just place shoe boxes along the bed and a blanket along the door so he cannot escape or hide. He does have a ball which we got gifted to us since our families know we LOVE our hamster. But they do not do their research like we have and did not know it was unsafe. Occasionally I will use it to get him out of the cage for cleaning if he isn’t feeling like he wants to be handled. My only issue with only
spot cleaning is I am very sensitive to smell so I can notice if his cage is even having a small smell. As I said I do keep older bedding in there and do a refresh once a month if not leas because I do it whenever I notice a smell. I just remove some if it once a week. That works best for me and he never had an issue. I have been looking on facebook marketplace to see if I can find a cheaper tank but so far all of them range around the same price. I am hoping to get a wider, and taller tank rather than bigger in length as he does have a smaller table/surface he is on. I also want to make most of the height since he does enjoy climbing things(I swear he thinks he’s a monkey or squirrel) So I want to create a multi tiered enclosure(obviously not too far where if he were to fall he would get hurt) but enough where he will have fun. I just cannot afford to drop $100+ out of nowhere at the moment. We got the Syrian on a whim we did originally want to get another dwarf which is in no way meant as a bad thing. The local petsmart had a lot of dwarfs that were either bonded(which the cage is not big enough for 2 dwarfs) or they were on their own but aggressive. This is my second hamster. I have had dogs, fish, turtle and a bunny growing up. I did so much research before purchasing my Dwarf and I do know dwarf hamster entail different needs that Syrians, I did as much research as I thought I needed but I kept the same schedule such as feeding, and cleaning as I did with the Dwarf. I could very well be cage rage, especially with the size if he is ready for a bigger cage. He doesn’t bite at the cage or anything and it seems the aggression is only towards me and my boyfriend. Which is what is confusing.

 

[Maz]

I think you're doing very well and you clearly love him and have experience from your previous hamster And things do need to be saved up for sometimes. For now it would be best just to make his current cage as cosy as possible with plenty of bedding, somewhere dark to hide (a house that's dark inside) some enrichment toys like tunnels etc and an 11" wheel. They do need a wheel in the cage.

The difficulty, if sensitive to smells, is that a smaller cage like this will get smelly quicker so I think that will improve when you get the larger one.

Have a look at some of the home page articles as they have a lot of info about the right type of cages and pros and cons etc. In particular, it is the floor area that's important for hamsters, especially syrians. So actually a smaller, taller cage wouldn't be good for him. The length and depth are the important things as it's more floor area for them.

Climbing just causes fall risks and hamsters are ground dwellers really. They will climb (usually just to see if they can find a way out and escape!) but they're not that good at getting down again and tend to just let go and drop so it does lead to injuries. A hamster cage shouldn't really be any taller than 20" (50cm) with about 20cm of that being bedding. If it's only 6" of bedding the cage could do to not be taller than about 45cm.

Could you rearrange some things in your home to fit in a larger/longer cage? Something like a 40 gallon tank would sit on a chest of drawers for example - it wouldn't matter if there is some overhang at the front/back/ends as long as most of it is supported.

In the meantime the out of cage time is important. But the bar climbing isn't that healthy really if it's a regular thing - it can also be a sign of stress.

My Syrians are in barred cages which are larger but they don't climb the bars because they're happy with the floorspace.

Ok so smells and cleaning - do you have a hamster toilet/litter tray? If not try getting one - they are inexpensive. I'll link the type that works well below.

It's just an open corner tray (make sure it's hamster sized and not a huge guinea pig one!).

You put hamster safe sand in that. Reptile sand is ok as long as it's calcium free. Desert sand and natural sand are popular (Komodo I think).

Sometimes a hamster will have a corner of the cage as their toilet. Syrians can be toilet trained. If you put the corner litter tray with sand in where he pees (is it a corner of the cage?). Spot clean the corner first by removing a couple of handfuls of pee'd on bedding and put a couple of new handfuls there. Put the litter tray in that corner, but put a very small bit of the old pee'd on substrate on top of the sand the first time, so he knows it's still his pee corner. He will probably start using it and then you just need to empty the tray every 2 to 3 days and the rest of the cage should stay clean and dry. They fit well in a corner and the hamsters can be very neat - mine used to pee in the very back corner where it's highest (so it doesn't splash out) and then sit in the front to have a wash.

Then you don't need to change the substrate very often - which saves money as well

Unfortunately pet shops do still give outdated advice about weekly clean outs and it really isn't good for the hamster. Have a look at some of the reviews for this one - people find it works

Hamster Corner Litter Tray

Sand for litter tray

 

[Maz]

How is your little boy today I hope he settles down a bit - I'd avoid clean outs for a couple of weeks and just spot clean the pee or try the litter tray. Another thought - have you been using scented cleaning products when cleaning the cage? This can really affect them. They have a much stronger sense of smell than us and sensitive respiratory tracts. And if the smell was overpowering for them it could affect his behaviour as well. They don't need disinfectants using unless there has been illness or disease and it's best to not use anything scented. Especially scented bedding or cage granules etc.