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Join our community of cat lovers on the Mumsnet Cat forum for kitten advice and help with cat behaviour.

When do cats reach full size?

38 replies

lizzieoak · 13/11/2016 17:32

According to googling it, its 9-18 months, however ...

I've never adopted young cats before, but we went looking for one new cat aged 5+ and somehow got two of about 18 months. They're now coming up to 3 and one has filled out to a pleasant plumpness, while the other (who used to feel too delicate to me - they're both boys and picking up the fluffy guy just felt like nothing, felt like he weighed 8 pounds, versus the 18 pound bruisers I'm used to).

Well, this winter the fluffmeister has suddenly started seeming much more muscular and solid feeling.

Do they still grow at this age? If not in terms of their skeletal structure, then in muscle mass?

OP posts:
cozietoesie · 13/11/2016 17:43

Seniorboy put on muscle when he came to live with me.

He was 14 at the time. Smile

lizzieoak · 13/11/2016 17:48

14? Gosh, I'll have a Great Dane if this keeps up then ;)

It just seems odd, after 18 months of being slight. As I said, I've always had big cats and would tell them in an encouraging tone that they needed to bulk up a bit. All that motivating talk has finally paid off :D

OP posts:
abbsismyhero · 13/11/2016 17:53

My youngest boy filled out more when he was 2/3 years old he was never as big as the oldest but definitely more solid

cozietoesie · 13/11/2016 18:21

Well he had a complete change of lifestyle, to be fair. Smile Has anything changed about your cat's - this year compared to last year, for example?

RubbishMantra · 13/11/2016 18:56

I'd say around 2. But IME they tend to eat more during the colder months, therefore acquiring a "winterskin". MCat looks like a plump teddy bear as I follow him down the stairs. He's a DSH (Moggy) Little M (Devon Rex) is compact, wiry, small and muscular, and they weigh similar.

Are your cats a particular breed? That can make a difference to growth rates. Especially the larger types like Maine Coons.

cozietoesie · 13/11/2016 19:00

And maybe it's been happening over - say- last winter but for some reason you've only recently noticed it?

BarbaraofSeville · 13/11/2016 19:00

About this time last year, we adopted a 2.5 YO boy cat. I'm sure he's got bigger this year, but it could be that I'm confused by all the kittens and young ones in the house as I foster rescue kittens and always have a selection of cats from tiny 6-8 week old to a few month old ones.

All the 6-8 month old ones that I have now seem almost full size, apart from one, who is tiny compared to the others - she's just under 2 kg and all the others are just over 3 kg. Big boy cat is probably about 5 kg.

lizzieoak · 13/11/2016 19:27

Cosie, no he's definitely bulked up. Some of it might be winter, though it's been pretty mild here this year.

Their breed is moggy :) Both bi-colours, brothers, one is fluffy and glam and the other is the short hair and the brains of the family.

Both are sulking at present as I squirted flea medicine on the backs of their necks and they are highly affronted.

OP posts:
lizzieoak · 13/11/2016 19:29

Oh, and nothing's changed so far as I know. I think they only get extra meals at one neighbour's house - & those neighbours are going on holiday soon so I'll be feeding them a bit more (though neighbours report that the Fluffy One is more just paying a social call whereas Brains is all about his tummy).

OP posts:
cozietoesie · 13/11/2016 19:46

Maybe he's just a slightly late developer then. Many animals - humans included - bulk up a little as they age. (Think to yourself of the difference between - say - the mature men you know compared to those in their late teens/early 20s.) I know that I hefted The Lodger recently and thought 'Blimey!' although he'd only ever seemed like a normal sized tom.

(Seniorboy is very sleek so easy to see the extra muscle he put on when he was younger.)

shouldwestayorshouldwego · 13/11/2016 19:55

I don't know but we have a fluffy and glam who seems to have been thinking fluffy thoughts when her mother tried to teach her how to be a cat. Her brother is a brainy short hair who despairs of his sister's incompetence as a cat and that he shares DNA with her.

FoxesOnSocks · 13/11/2016 19:56

I'd think Ginger Giant has always been big if it weren't for the pictures. He's 2.5 and weighed 5.5kg at his booster visit (he's not a fatty though) which was just after he was 2. At his boosters the year before he was just over 4kg.

I'm hoping he's stopped growing now or I'll have to invest in a bigger carrier and cat flap!!

FoxesOnSocks · 13/11/2016 19:57

Oh yes he's a domestic short hair

FuzzyWizard · 13/11/2016 20:05

Is ginger giant a Maine Coon by any chance? If so you've got another 18 months of growing. We were warned when we adopted ours from the rescue that she will likely keep growing until the age of 4. A moggy would normally be finished growing by 2.

OutrageousFlavourLikeFreesias · 13/11/2016 20:11

My older cat has quite a lot of British Short Hair in her and she kept growing until she was at least three. She was a little slinky small thing when she came and is now approximately the size of a small bear. My younger cat is about eighteen months old, and seems to have stopped growing and settled into a small sleek muscly shape. When they sit together they l look ridiculous. Grin

cozietoesie · 13/11/2016 20:22

I guess that all you need is one Maine Coon Lad whose owner didn't neuter to time and who escaped in order to party? Grin

FoxesOnSocks · 13/11/2016 20:25

No FuzzyWizard 'domestic short hair' is what I was told in his first vet visit at 5 weeks (after being discovered alone)

FoxesOnSocks · 13/11/2016 20:27

... Admittedly this does mean his parenting isn't known!!

cozietoesie · 13/11/2016 20:30

I felt unconscionably pleased when The Lodger was classed as a 'DSH' on his first vet visit. Grin

FuzzyWizard · 13/11/2016 21:01

I suppose a DSH could be a mix of all sorts. A little while back Maine Coon would be unlikely to feature much in the moggy gene pool but there are so many of them around now that you could well have a future 8kg monster on your hands. Grin

cozietoesie · 13/11/2016 21:20

PSST - a DSH is really a moggie. The vet was just being polite. Grin

cozietoesie · 13/11/2016 21:22

But Yes - you're right. You have no idea what you're getting. Even from the same litter! Grin

coxsorangepippin · 13/11/2016 21:28

I thought my moggy was full grown when I got him as he was cat-sized... Turns out he is half Norwegian forest cat and the little bruiser now weighs a stone and can jump five foot vertical from a standing start!

(Hello MNers - I'm new here)

BarbaraofSeville · 13/11/2016 21:31

Isn't DSH just another word for moggie/crossbreed/non-pedigree? Although I don't know what you're supposed to call long haired non-pedigree cats? One my previous fluffy monsters was listed at the vets as a DSH, which didn't seem right.

BarbaraofSeville · 13/11/2016 21:36

Even in the same litter they can have different fathers. I have 2 from same litter and one is twice the size as the other and even though both are black, one has a shadow of tabby markings in his fur.

Another pair of brothers we had years ago, one was big, black and white long haired and the other was much smaller and tabby and white.