Lobsters have two urinary bladders on the sides of their heads, which excrete urine through a nozzle-like structure called nephropore rosette. Interestingly, they are capable of spraying urine up to seven times the length of their bodies into the water. Lobsters also use their hairy gills on the front of their exoskeleton to direct urine further into the water flow.

Lobsters fight using their antennas and claws during performances and battles, while clawless lobsters fight with their antennas. When lobsters compete, various aggressive behaviors can occur.