Crawfish communicate with each other by shooting streams of urine out of pores on the sides of their heads. Clusters of fan-like appendages direct the spout straight into the face of the other crawfish during a fight or during courtship. The urine contains hormone derivatives that give clues to the sprayer’s current level of fitness, and indicates whether or not that particular crawfish would make a fearsome adversary or a healthy mate. (And aren’t you JUST glad you’re not a crawfish?) (From Ripley’s Believe It Or Not: Eye-Popping Oddities)
Sylvia Shults, author 