Deceptive Male Crayfish With Large, Weak Claws Win Fights by Trickery

Posted on March 24, 2012

Crayfish Fight

Researchers have found that male crayfish often win fights by intimidation alone. Some male crayfish possess enlarged front claws that they use to intimidate their competitors. The researchers found that these enlarged claws are not as strong as they appear. The males routinely bluff their opponents with these large, weak claws to achieve dominance.

This is not the case with females. With female crayfish, claw size is a strong indicator of claw strength. The scientists measured the size and strength of claws of both male and female crayfish, and then monitored how they performed in competitive bouts. For female crayfish the size of the claw was an honest indication of how strong they were. However, claw size of males was not a good indicator of their strength.

LiveScience reports that the larger princers are often made of a lower quality muscle than the smaller pincers. Michael Angilletta Jr., of Arizona State University, told LiveScience that a strong male crayfish with small pincers will sometimes run away from a crayfish with larger, but weaker pincers.

Robbie Wilson, lead author of the study, says, "Male crayfish lie and cheat their way to the top, whilst females appear to be honest displayers of their own strength. This is important work showing that dishonesty is commonly used by animals during fights. We already knew humans often use dishonesty during disputes, but our results suggest cheating may play a more important role in animal communication than previously imagined."

Photo: Anthony O'Toole, The University of Queensland

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