Cymothoa exigua is a type of parasite that enters through fish's gills, eats their tongue, and then replaces it.
6
Cats and dogs can hear ultrasound.
350
Baks the blind boxer has a seeing eye goose named Buttons; a four-year-old goose who leads the pup around everywhere either by hanging onto him with her neck, or by honking to tell him which way to go.
16
Allegedly, Chrysippus, the Greek philosopher, died of laughter after getting his donkey drunk and watching it try to eat figs.
47
Lobsters have blue blood.
476
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