Mongoose

The banded mongoose engages in some pretty significant warlike behavior that starts with a screech and can end in death. Now, researchers have uncovered a different not-so-nice behavior exhibited by the animal: When females are kicked out of the group, close family members are often the first to go.

New research makes a day in the life of a banded mongoose sound like an episode of the TV show, Vikings. Turns out the little critters engage in some pretty serious gang-like behavior that leads to death, sex between enemies, and an odd life-preserving side effect.