Is there such a thing as an SEN cat?

[BritBratGrot]

Not educational obviously, but not sure what other phrase to use.

I mean a cat who is significantly below average performance mentally

We've got two kittens recently and they're both gorgeous. One of them was definitely the runt of the litter and he just doesn't play in the same normal way his sister does. He wanders around and then just sits and stares kinda vacantly. He's very placid and eg doesn't play fight back when she pounces on him. I don't think I've ever really seen him 'play'. Though having said that I think he was just this second playing with his sister's tail, but that's honestly the first time.

He doesn't bury his plops in the litter, she does. He wanders off regularly during dinner, she doesn't.

He is noticeably smaller (just 650g to her 1000) at nearly 12 weeks. They got a sniffle and had a temp last week which they're both just recovering from.

The charity which rehomed then to us assure us the vet gave him a clean bill of health, though the foster worker thinks he's got a different dad from the rest of the litter and might have been premature, he looks different from the rest of them.

Is this a thing in cats?

Yes. My parents had a cat Henry who had cerebral palsy and extra toes due to being found as a feral kitten in the wild where inbreeding had occurred.

My parents adopted him and his sister Sophie and Sophie was just very tiny but all there and Henry was slow on the uptake but lead a full and active life.

We also had in our family a dog with mild cerebellar hypoplasia due to oxygen deficiency at birth (ended in a c section for the mother as one puppy was stuck, and that puppy I believe died). She walked with an odd wide legged, slightly stiff gait to balance better, but it never seemed to bother her much, she was a happy if somewhat strange girl and lived to the expected age for her breed.