When cats are happy, they may squeeze their eyes shut.
10
One reason that kittens sleep so much is because a growth hormone is released only during sleep.
212
Some lizards, in which the tail is a major storage organ for accumulating reserves, will return to a dropped tail after the threat has passed, and will eat it to recover part of the sacrificed supplies.
13
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
The colossal squid has the largest eyes in the world.
4