We grew up with dogs, not cats, and one of my sisters had this Great Dane who had huge litters. Once she had 14, and one died, and my sister took it out and buried it while the mom wasn't looking. That dog searched for that baby for weeks, rounding rounding, just hunting forever. Never found the grave. The next litter (15), one died, and my sister showed her the dead puppy, which she sniffed once. Then sis disposed of that poor wee one, and the dog never looked for it at all.

(slightly more creep) That dog could count, and multiply, and divide. The time they had puppies while stateside I went to midwife, and 12 babies were born (one was born dead but we CPRd it back). The dog would keep the puppies either in 2 piles of 6 or 3 piles of 4, feeding one pile while letting another sleep and the third, if applicable, romp. She seemed to know all the individual smells. You could move puppies between piles while she wasn't looking, and she'd switch them back. If you took one and didn't put it anywhere, she'd seek till she found and then put it in its correct pile. It was too cool.