Some older/less efficient worker termites will develop 'backpacks' of toxic chemicals that explode when the termite is threatened. They are essentially used as suicide bombers when the colony is being attacked.
8
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
A group of unicorns is called a blessing.
304
In 1955, the citizens of São Paulo were so upset with their government that they elected a rhinoceros named Cacareco (meaning rubbish) to the city council in protest, with over 100,000 votes.
18