Siamese cats have dark appendages, ears and noses due to a hormone which is temperature relevant.
A cat will come and rub its cheeks or lips on you to mark you as territory. The reflective part of a cat's eye is called a 'tapetum'. It enables a cat to see many times that of a human at night by sending the light back through the retina. Very young kittens cannot go to the bathroom by themselves. The mother cat stimulates them into going by licking their genital area after they've eaten.