Brother/sister cats suddenly hate each other

[CoffeeChocolateWine]

My beautiful kitties turned 1 in July and we’ve had them since they were 9 weeks old.

They had formed a bond when we adopted them and up until a couple of months ago they were really friendly towards each other. They often played together, slept together, groomed each other etc.

But over the summer it has seems like something switched and they really dislike each other. They are hardly ever together and when they are there is hissing and more aggressive squabbling than the ‘play fighting’ they used to do.

i can’t understand what’s happened. Is this normal for boy/girl cats? They have very different personalities but both very friendly and affectionate to us in their own ways, but just not towards each other. Is this how it’s going to be now…two cats that don’t get along, or is it a phase and at some point they’ll bond again?

We’ve never had cats before these two so if someone with more experience could shed some light I’d appreciate it!

Anyone? 🙏

We have a brother and sister cat and sometimes they fight, usually every couple of days. It can be either of them that initiate it. However if one of them is in trouble, like getting shut in somewhere in the house, or inadavertently shut outside, then the other one gets very unsettled and starts acting up to alert us.

When they were little they used to sleep together. Now they both sleep up on the landing outside my bedroom but at opposite ends, the boy in his cat bed and the girl either on the carpet outside my room or in the winter she sleeps in the airing cupboard which is also on the landing.

Downstairs they divide on gender lines, the boy sits/sleeps on the sofa with my husband and the girl sleeps/sits on my sofa with me. They both like sitting on the window sill and looking out at the traffic lol!!!!

They kind of have a love/hate relationship!

That’s interesting. So they have become more independent from each other as they’ve got older, but it sounds like there’s still a bit of affection between them! With my two, it just feels quite hostile. They are very rarely together and if they do happen to come together - to eat for instance - there is hissing and they separate. It seems to mostly come from the girl towards to the boy from what I’ve seen.

They are both lovely cats individually…the girls is more independent and adventurous, spends more time outside, likes being stroked but not being picked up, and sometimes climbs on our laps in the evening. The boy cat is more affectionate and needy, loves cuddles and tummy rubs, slightly more dopey in personality and prefers to curl up by feet rather than laps. I suspect he’s part dog 😆 So they are very different personalities and the boy is a much bigger cat. I just miss them being affectionate with each other!

Normal in my experience that they fall out at about 1yr old. I know people with sibling cats that loved each other lots thru adulthood but none of mine ever did. Mine end up bullying or hissing etc. at the other one.

My last 2 pairs were 1st x 2 boys, 2nd x 2 girls. The relationships ended up with:

Friendly to brother but also Persistent Bully vs. "I hate your guts & growl or hiss if you come near"

Occasional bully but only about food vs. "I couldn't care less about you" shrugger

The sibling cats (both boys) I had when I was a kid became fairly indifferent to each other, I don't recall hissing or bullying.

I assume they’re both neutered and have access to the outside?

Do you have plenty of resources for them to share indoors - several litter trays, beds, scratching posts etc?

Yes, they were both neutered at around 5 months and we have a digital cat flap that lets them in and out as they please any time from early morning till 9pm and then it locks and keeps them in at night.

They have a shared feeding area (but don’t tend to eat there together at the same time), litter tray, bed (although neither of them really use it anymore) and scratch post. They both have free rein of the house and have their favourite spots (in different rooms).

I don’t feel like there is ‘bullying’ as such, just hostility. From what I’ve seen it mainly comes from the girls towards the boy (growling and hissing), so doesn’t seem like male dominance and she is much smaller in size compared with the boy. It’s rare that they physically fight…they just seem like housemates that have to tolerate but dislike each other so avoid as much as possible but occasionally have cross words!!

Interesting to read about the dynamics between other sibling pairs. Thank you.

When we got our (female) cat it was from a family who had got a sibling pair and they had “fallen out” around 18 months — apparently this is quite common for some reason! They had been very close as kittens but on getting to adulthood the (bigger) male cat started bullying the female cat, and they no longer got on well but hissed and wouldn’t sleep or play together. They were indoor cats so the female in particular was really suffering from the tense atmosphere. I don’t know why this happens but apparently it does!

Also, any bullying may not be immediately visible. A smaller female cat may well feel threatened by a bigger male cat who take up more resources and space than her. In the case of our two, it wasn’t like the male (who was quite cheerful and friendly) was necessarily being overtly aggressive — but if you looked carefully, he ate more food than his share, he didn’t always let her get to the food/water without crowding her, he monopolised the toys so she couldn’t play with them (including taking them off her when she tried to play); he got more attention and the best sleeping places, and she wasn’t always comfortable using the litter box with him nearby. In that situation no wonder the smaller cat is tense and defensive. Watch them both carefully to see if there are times when he grabs her things/food, intrudes in her space or monopolises your affection or space, as that’s also a form of cat bullying!

I have had sibling cats plenty of times as well as ones unrelated to eachother and non of them have cuddled up together past around 6 months to a year old. The best we tend to get is acceptance, if fact one of the reasons I realised the cat we had PTS last year was so ill was that sh didn't swipe at her sister when she sat near her!

Maybe it’s natures way of making sure inbreeding doesn't happen?

We have boy and girl siblings, and same as you initially they played together and cuddled up together. They had a brief period of hissing and swiping but they are 7 now and just tolerate each other - boy cat is definitely the more dominate and girl cat doesn't come in room we are in if he is already in there etc.

I've said before on here that I think she would be much happier as a single cat.

Nature doesn't seem to care about that. Unneutered cats will happily shag close family members. Also, in the wild, feral cats live in large family groups. So, whatever the cause, it's not that.

@CoffeeChocolateWinefor two cats you need three litter trays, multiple feeding stations and resources like beds, scratching posts etc.

Our first cat was a male who moved in with us because he was bullied by his much smaller sister.

I think it’s so funny cats are adopted as bonded pairs, then end up hating each other. My friend has a mother and daughter cat and they only tolerate each other also.

Thank you so much for all these comments…it is quite eye opening actually.

@greengagesummers, your comments about the smaller female cat feeling threatened by the bigger male particularly resonated and I do wonder whether that might be what is going on. Because he does tend to take up more space and resources, eats more than his fair share of food and monopolise space and affection. I had put that down to differences in their personality but now it seems very possible that she feels tense around him, prefers to be outside because of that, and the growling and hissing is defensive rather than aggressive. I really hadn’t considered it 🤔

@tumblingdowntherabbithole, I had no idea 🤦‍♀️ They only have one feeding station but with two bowls each for dry and wet food and a shared water bowl. I do give them their treat food separately otherwise she would never get to eat it, but otherwise they just come and graze when they want to. We also only have one large litter tray but both tend to go outside more often…they only use the tray at night. Again, thanks for your comment…I’m definitely still on a learning curve!

@CoffeeChocolateWine have a look at Jackson Galaxy’s stuff - he’s a bit woo and it’s mostly aimed at indoor cats but he has lots of good suggestions about making sure you have plenty of resources and cat “super highways” so they can easily pass each other etc. without feeling threatened.

My 4 year old boy cats were fighting a lot. One was the aggressor. Have been experimenting with cat pheromones for last couple of weeks after trying all the other things recommended like making sure they weren’t competing for resources.

We have a plug in version in living room and have tried a drop on solution on aggressor as many attacks were when they were both in garden (so plug in wouldn’t work there). They’d both be chilling, then out of nowhere, one would attack the other)

It’s early days but seeing an improvement.

Yes, cat territory and behaviours is all bound up with how secure they feel not just in “their” space, but also “their” resources like food, water, litter box, sleeping places, toys. If a bigger cat is taking more of something that she perceives as her only access to food, water, spaces, etc., then the smaller cat will feel constantly tense and on edge because it’s like she’s constantly living in someone else’s territory. Hissing in cats is largely a defensive behaviour, a “back off” signal, rather than aggressive, so that’s probably a sign of what’s going on.

Could you give her a separate litter tray, different space to have her food or stop him taking hers, and give her plenty of toys and play when he isn’t around? Our cat’s previous owners said she didn’t play, and would only watch her brother playing. But I saw her trying to get a toy and the brother came and took it off her! When we got her home to our house, she played with toys for four hours straight the first night, and we realised she did want to play, she just wasn’t getting to because the bigger brother cat was making sure that the toys were “his”, not hers.

This page has a good explanation but there is loads of stuff online about cat behaviour to look at too. Basically because cats mark territory by scent and subtle behavioural signals, it’s kind of invisible to us if one cat has taken more space or is “owning” a territory (which makes other cats in the territory feel threatened and defensive). So we don’t always see what’s going on with the interaction under the surface. There are ways of redistributing the territory to reduce tension, like evening up resources and affection given to each cat.

https://classactcats.com/blog/cat-territorial-behavior/

This is good too:

https://icatcare.org/articles/multi-cat-households

@greengagesummersthank you so much, this is so helpful 🙏

Everyone says get kittens in pairs and I'm sure there are lots of benefits while they're babies. But when I was little I had brother cats who didn't like each other as well. It seems quite a gamble as they do often seem to fall out as they mature and I think many cats do prefer to be the only cat in the house - my childhood cat was over the moon when his brother was run over.