Only 3% of bird species have penises.
0
Sloths take two weeks to digest their food.
243
A newborn Chinese water deer is so small, it can (almost) be held in the palm of a hand.
13
The oldest known animal in the world was 'Ming' the 405 year old clam, discovered in 2007.
492
Sergeant Stubby was the only war dog to be promoted to sergeant through combat in WWI. He saved his regiment from surprise mustard gas attacks, found and comforted the wounded, and even once caught a German spy by the seat of his pants, holding him there until American Soldiers found him.
16
Parrot parents "name" their children with a signature call.
112
Cymothoa exigua is a type of parasite that enters through fish's gills, eats their tongue, and then replaces it.
6