Cats are hypercarnivores
Cats are the only known mammals that are unable to taste sweet things. Cats lack two genes known to encode the ability to taste sweetness: Tas1r2 and Tas1r3.
Cats can form mental maps of where their owners are in the house based on sounds. They make look like they are snoozing away but cats will track your location in the house by listening for you.
Cats can not only learn their own name, but they will learn the names of other people and animals in their household.
Feather wands
Cats who prefer to hunt birds love feather wands.
crinkle toys
toys that crinkle mimic the sound of mouse for cats that love to hunt rodents.
lasers
Cats who love to chase bugs love to chase after laser dots.
Cats prefer to play with toys that mimic the movements of their preferred prey to hunt.
Kittens from the same litter can have different fathers. When a female cat goes into heat, she will release multiple eggs and can mate with multiple males.