So my sister wants to adopt a little kitten that is roughly 3 weeks old. My fear is, our cat is somewhat of a murderer. He just kills for fun and not eating.

You may see him hunt a rat, slash the back, make the rat run, then slash the hind legs and make the rat run again, until he cuts off the rat's legs. He will then finish off by opening the skin of the rat, but you can actually see that the rat is still alive, but bloody.

Another example is a chick. He cut off the wings and one leg of the chick and watched the bird die, then walked away.

The cat kills anything that he can from rats to birds to lizards as big as 2 inches.

We took the murderous cat when he was a baby, and the only friend that he has is our 12 year old shitzu.

The cat is 4 years old now. I am thinking that the kitten might be mistaken as a rat and the cat might kill it. Or the cat might kill it because he might become jealous. But my sister insists on adopting the kitten even with my warnings. With this kind of cat in our house, should we adopt the kitten or not?

  • 13
    From what I've read (and this is probably Wikipedia zoology, so you may not wanna take it too seriously) cats play with their prey in this way in order to weaken it before they actually kill it. This is so they don't have to stick their vulnerable faces with their eyes and ears and so on into the way of flailing claws and biting teeth. I don't think your cat is a monster which can't be trusted with other cats - at least, no more so than most. what i'm saying is there's nothing necessarily specially awful or worrying about this behaviour of your cat
    – Au101
    Commented Jun 7, 2018 at 12:34
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    Good luck with your sister, but kittens can be very adorable. Maybe let do research on best kitten care? 3 weeks is really to young! Commented Jun 7, 2018 at 13:13
  • 18
    Just to reframe your interpretation, there's probably a PetOwners.SE site where your cat is asking if it's a good idea to live with humans that eat cows and chickens, and kill other animals for non-nutritional purposes.
    – Flater
    Commented Jun 7, 2018 at 13:53
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    I don't see anything described that is abnormal for cats.
    – user12271
    Commented Jun 7, 2018 at 14:06
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    the problem here is the kitten is way too young to be adopted it needs to be 10-12 weeks old before you even think about adopting it.the older cat is not the problem,cats do hunt and kill prey and kittens are not prey,but they are competition and might be driven away by the older cat. Commented Jun 7, 2018 at 14:35

5 Answers 5


First, step back and read up on best ages for kittens to leave their mother. (The best age to adopt a kitten is around 10 weeks.)

At 3 weeks of age a kitten is completely helpless and will need help with every thing from keeping warm to drinking (it cannot eat yet) and relieving itself. Till 6 weeks you are just fostering a kitten, let the mother take care of the kitten, please. Weeks 6 to 12 are needed for socializing from the mother.

Your cat seems to have no problem with a (very) small dog. So I think you can introduce an other cat into the house.

Then becomes the question: how to introduce a new cat into your home? That can be done, but it will take time. Experiences vary, mine was about 2 months before my 2 cats could safely be in one room...

Good reads on this topic:

  • 7
    Even if the kitten is orphaned (in some cases "adopt" would imply that, but not in others), it needs specialist care at that age. And (almost) all cats are murderous in the sense of the Q.
    – Chris H
    Commented Jun 7, 2018 at 13:29
  • We actually took the old cat in when he was 3 weeks old, it seems like its better to have them this way because we can train him based on what we wants, but being an alarm clock is something he learned himself.
    – Mr.J
    Commented Jun 8, 2018 at 0:52
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    @Mr.J unless you wanted a cat that would murder everything in sight I don't think your plan worked particularly well. I definitely agree you shouldn't take a kitten so young.
    – Muzer
    Commented Jun 8, 2018 at 13:22
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    10 weeks should be considered the minimum age to take a kitten from their mother. 12-14 weeks is better. Commented Jun 8, 2018 at 13:23
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    Second on that. Both breeders of our two cats would not give them before 14 weeks, and that is right. They are excellent cats without any of the problems or bad habits I hear other cat owners complain about. Those socializing weeks with the mother are absolutely essential.
    – Tom
    Commented Jun 10, 2018 at 5:50

The fact that the old cat is friendly with the Shih Tzu means that there's good hope that he will tolerate the kitten.

Start by bringing things that smell like the kitten into the old cat's space, like towels and bedding. Later, when the kitten is old enough to be separated from the mother/family, bring the kitten into your space in a locked carrier, so that old cat can get all of the sniffing and hissing out of the way. That's normal. Keep the kitten physically safe and make lots of friendly noises, and the old cat will start to acclimate.

Beware: the old cat will teach the kitten. You will have two murder cats. This is normal cat behavior. If it distresses you, don't get the kitten.

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    I see cats more as "In house pests assassins", as hobo's tend to be migratory... Commented Jun 8, 2018 at 8:23

Cats view other cats differently than they view prey animals. While cats aren't the socialization machines that humans are, cats, like humans, form social groups and bond with other cats. Also like humans, sometimes cats just hate each other and there's nothing you can do.

Aside from the above advice of "wait till the kitten is old enough to ethically re-home it", you should be willing to give it a whirl and see how things play out. Your cat might be a complete love to other cats. Your cat also might be an anti-social jackass. The best you can do to determine this is introduce the cats to each other in a supervised and gradual fashion. There are lots of guides online, but essentially you want to introduce their smells to each other, then sight/sound of each other, then physical access to each other. Don't move to once stage until the cats no longer care about the previous stage - that is, if they're giving each other the Hard Stare through a fence, don't let them physically access each other, they'll get stressed out and just hiss at each other.

As an aside, all five of my cats will routinely leave murdered mice around my house - sometimes intact from a blow to the back of the neck, sometimes a literal pile of gore. (Somehow I've managed to not step in those yet...) They are all various degrees of social but I can occasionally find all of them snuggling with each other on cold days, despite them being murderhobos to anything small and not-feline.


It might sound awful but your cat does what his instincts tell him.

A rat is a dangerous creature. It's smart and can bite quite severely. Attacking it from behind, weakening it, and making it almost die from blood loss is a safe approach for a cat.

A bird is also a dangerous creature. It has claws and a hard beak that can do a lot of harm. It can fly (or at least try to). Again, weakening it is the strategy to use.

We are against such approaches but these are natural mechanisms. Also, a cat's instincts work regardless if it is hungry or satiated. A satiated cat can actually be more deadly since it has sufficient energy to hunt efficiently.

This doesn't mean that a cat will treat other cats as prey. That's not what cats do, so other instincts should be at work here. The kitten will act as a cat does (especially if it is grown enough) so the two will be able to communicate in the same "language".

Anyway. your cat might want to show the kitten its place in the herd, so the introduction of a cat at home should be gradual. Start with scents. Then your two cats should be physically separated (but hear, smell and preferably see each other). A large cage for the kitten is a good idea. It can stay in such a case for weeks without much harm. Socialise the cats with each other only when you have full control over the situation (and do not overestimate your capabilities - cats are extremely agile and smart too so they can fool you). When the older cat no longer poses a threat to the kitten, you might start leaving them alone (again, at first just mock it and monitor situation), then gradually leave them together more and more unattended.

In general having a second cat is a good idea. It channels some of older cat's energy (sometimes fights might look violent but that's also normal. You have to learn how to recognize if cats are playing or really fighting).

As for age, 3 weeks is way too little for a cat to be taken away from its mother. Unless there are serious reasons to do otherwise (the mother was killed, has a high risk infection or is aggressive towards its litter or specific kittens) the kittens should stay with mother until they are 12 weeks old. 8 weeks is the absolute minimum.

At the age of 12 weeks kittens no longer psychologically suffer from being detached from their mother. If it happens earlier, they may suffer from orphan disease, negatively affecting their behaviour (among other things increasing a risk of aggression).

At the age of 8 weeks kittens are fully transferred to eat solid food and do not need a supply of mother's milk. Taking kittens earlier negatively impacts their immune system and at an earlier stage it is a life threat as you can hardly replace the mother's milk with any substitute. Specifically don't try using cow milk. It can cause diarrhea and lead to dehydration and death of a kitten. Moreover, such small kittens should be fed every 2 hours. Can you do that (at night as well?)

The earlier kittens are detached from their mother the larger are the negative effects. Be a responsible pet owner. Resist temptation to have a nice cuddly kitten and take it until it's really ready. If you really want to take a smaller kitten, adopt one that really needs it (for reasons given above). Still I would avoid taking kittens smaller than 5-6 weeks unless you really know what you're doing.

So please, rethink the idea of taking so small a kitten.

  • 1
    "If [they're separated] earlier, they may suffer from orphan disease, ... (among other things increasing a risk of aggression)." OP said they got their current cat at 3 weeks. I think we just identified why it became a murder cat! (Besides the whole "being a cat" thing, of course.)
    – Kat
    Commented Jun 9, 2018 at 17:15
  • I know and that was one of the reasons why I wanted to point it out.
    – Ister
    Commented Jun 11, 2018 at 7:35

I have been around literally hundred of cats in my lifetime. To answer your question directly I will say that there is almost 0% chance your cat will kill a kitten as I have never seen it happen. I can also say that there is a 90% chance that your cat(s) will be very mean to the new kitten. It my mind it is a way for existing cats to say this territory is taken, move on.

The worst I have seen this is from a female cat, especially one who has had at least one litter. An existing female to new male is the worst I seen.

There is a slight chance that the new cat will be 'adopted' given its young age but I have only seen that on TV or videos never in person.

Depending on your cats personalities there is a chance the new cat will be tolerated if it does not try to attack 'play'.

Also I wouldn't worry about the murderous aspect. In my experience many cats will treat prey this way, especially females. I always believed that was because mothers are in teaching mode, disabling but not killing prey is good for training kittens.

As for not eating the kills, if your cat was not well fed you would find that the kills would indeed get eaten.

  • 2
    Really, you've never seen a cat get along with a kitten? My family had lots of cats growing up, and older cats generally tolerated the kittens if nothing else. If the older cat still liked to play, they often loved the kittens.
    – Kat
    Commented Jun 9, 2018 at 17:19
  • I did say 90% that's 9 out of 10 not never. I am also talking about what I would call 'normal' urban households where more than 2 cats is very rare and more than one is uncommon. In cases where cats are used to living with many other cats it could be different. I have seen that different environment on the farm where I buy local produce. There the cats seem to stay out of each others way unless they are litter mates and they live mostly outside / in the barn.
    – Joe
    Commented Jun 11, 2018 at 12:27

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