Naked mole-rats have a high resistance to cancer tumours because they produce an extremely high-molecular-mass hyaluronan and have ribosomes that produce extremely error-free proteins.

Lionesses are caring mothers who will even take care of a neglected cub, allowing him/her to suckle and giving them a chance to survive. Two or more lionesses in a group tend to give birth around the same time, and the cubs are raised together. Cubs are extremely playful.