Don: Hey Ya?l, here's another one for your "strange but true" file---Lobsters and      crayfish communicate by shooting streams of urine at each other.

Ya?l: Eew. This better be a good one, Don.

D: It's actually pretty neat.Many animals produce chemical signals for communication.      These signals, or pheremones, can carry information about mating readiness or      dominance status. Lobsters, crayfish and other crustaceans send these signals      packaged in streams of urine.

     British researchers studying signalling behavior in crustaceans discovered that      crayfish could shoot streams of urine out of pores on the side of their head. Clusters      of fan-like appendages near the mouth direct a highly focused stream straight into the      faces of others during fights and courtship.

Y: That's an unusual communication strategy.

D: Well, their urine contains hormone derivatives that can tell others a lot about the      fitness or current state of the shooter---useful information when choosing a mate or      when deciding whether to fight or back down.

     The researchers studied the role of the chemical signals in fights between pairs of      crayfish. They found that "Winners" of fights shot more chemical signals than "Losers"      in fights. But when the urine of crayfish that were normally "winners" was blocked,      they started to lose fights. If their urine pores were then unblocked, they became      winners once more.

Y: Interesting!

D: If you think that was interesting---tune in next time to learn what urine signalling in      crustaceans has to do with NASA and odor-tracking robots!