One reason that kittens sleep so much is because a growth hormone is released only during sleep.
212
Shark corneas are used in eye transplants and shark bone marrow can be used to graft human bones.
132
A banana slug can be 6-8 inches and their erect penis can be just as long. Also, their penises emerge from their heads. After sex, banana slugs eat each others penises.
17
Blue whale arteries are large enough for humans to swim through and their hearts are the size of cars.
12
Ants have tiny magnetic compasses in their antennae which help them navigate.
9
A giraffe's kick is so powerful that it can decapitate a lion.
216