The cat brain weighs about 30g.
167
Dogs have been man's pet for over 14,000 years.
224
When cats are happy, they may squeeze their eyes shut.
10
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
Cymothoa exigua is a type of parasite that enters through fish's gills, eats their tongue, and then replaces it.
6
A newborn Chinese water deer is so small, it can (almost) be held in the palm of a hand.
13