Crabs will fake it to avoid a fight

Crabs will fake it to avoid a fight, research finds Dr Robbie Wilson, Head of the Performance Lab at UQ, where this study was conducted, said the research identified more than just some crabby behaviour. “This study is important because it reveals the general principles behind how liars and cheats are controlled and encouraged in nature.“Whether it's a soccer player diving to fool a referee or a crab trying to intimidate a rival with weak claws, our lab has shown that individuals cheat more when their deception is likely to go undetected,” Dr Wilson said.

Ms Candice Bywater who is finishing her PhD on fiddler crabs, said that she found that more males bluff their way through fights when they are less likely to get caught.

“When there are lots of crabs living in one area, there is lots of competition for resources like females and food. High competition means there is a greater chance of males having to fight each other to win resources compared to when there are not many crabs about. Those crabs might not have to fight at all,” Ms Bywater said.

“Crabs that have strong claws will generally win fights. Producing large and strong claws is important to their survival.

“Where crabs are likely to have to fight a lot, the crabs are producing large, strong, reliable claws. We found that when there are not many other male crabs in a population (low competition), males produce large but relatively weak claws (unreliable), as they don't have to fight as often and ultimately because can get away with it."

In nature, signals may be behavioural, as in growling or posturing, but are often structural, including the antlers of a deer, and the enlarged fore-claw of many crustaceans.

A male that overstates his quality could improve his ability to gain food or mates, but surprisingly, most signals are honest reflections of a male's prowess.

Written by UQ Media

Tackling the Problem of Diving in Football

Some consider it an art form, others cheating. Whatever your thoughts, diving by soccer players is one of the most controversial and despised actions in sport. Diving represents a deliberate attempt to deceive the referee, with players falling – even rolling around - to suggest they’ve been illegally fouled. Diving has long been a source of embarrassment for the world’s most popular sport, yet even football’s governing body (FIFA) has had little success at stamping out this behaviour.

University of Queensland PhD student Gwendolyn David, along with her supervisor Dr Robbie Wilson and other UQ colleagues have taken a fresh look at diving behaviour in an attempt to identify the mechanisms that can be used to control it.

In a study published this week in the prestigious open-access journal, PLOS One [] these researchers explored the behaviour of soccer players and referees in the context of animal signalling theory.
“Theory predicts that deceptive behaviour should occur only when the prospective benefits outweigh the costs and when the risk of detection is low,” says Ms David. “So we expected that deception would be driven by the potential payoffs and would be limited by punishment.”

David undertook a play-by-play examination of 60 matches across six high-profile professional leagues to see when and where players faked fouls, and when they were likely to get away with it (or not). She found that – as predicted - diving occurred most often when the potential payoff was greater: namely, in the offensive side of the field and when the two teams had tied scores.

But the most exciting result came from looking between the leagues. “We found that players dived more often in leagues where referees were more likely to reward dives with a free-kick or penalty,” says Dr Wilson.

This means that when referees don’t detect or punish diving then dives are more common. “The most effective means of controlling deception, whether it’s a footballer or an animal, is via punishment. But, of the more than 2800 falls we observed and the 169 dives, we never once saw a diving player punished,” says David.

“Our results clearly show that reducing deception in sports like soccer is largely up to the referee and governing bodies. Players will try to deceive referees when the benefits are high, but better detection and administration of punishment may help reduce its prevalence” says Dr Wilson.
“Some progressive professional leagues, such as the Australian A-League and American MLS, have already started handing down punishments for players found guilty of diving. This is the best way to decrease the incentive for diving,” said Dr Robbie Wilson.
For more information on the study or for interviews, please contact Dr Robbie Wilson (Senior Researcher) at +61 458204962 or For other information on this research group’s work see the lab soccer website:

Animal Signalling

We're giving signals whether we know it or not. All the time - and without saying a word - we show others that we're bored or interested or infatuated or annoyed ... And this ability certainly isn't unique to humans.

Signalling is pretty much everywhere in the animal kingdom.

We know that some organisms use displays or calls or body structures to attract mates ... or ward off intruders ... or show how wonderfully strong and appealing they are. (Hmmm ... can you think of any examples?)

But what scientists are starting to figure out is that not all these signals are - shall we say - honest. Sometimes appearances aren't the same as reality. And there are times when it pays to show what you might be, rather than what you actually are. We're studying dishonesty in signalling in a number of different research systems, including crabs (who signal strength via their claws) and soccer players (who signal fouls via dives).

photo by Skye Cameron

You can read more about our signalling work here:
Cheating pays off for females but not males
How humans differ from crabs

Or here:
Walter G, Van Uietregt V, & Wilson RS. 2011. Social control of unreliable signals of strength in males but not females of the crayfish Cherax destructor. Journal of Experimental Biology. 214: 3294-3299.

Wilson RS & Angilletta MJ. In press. Dishonest signals of strength. In Ed. D. J. Irschick, M. Briffa, and J. Podos. Animal Signalling: a Functional Perspective. Ralph Wiley Press.

Wilson RS, Condon CH, David G, FitzGibbon SI, Niehaus AC & Pratt K. 2010. Females prefer athletes, males fear the disadvantaged: different signals used in female choice and male competition have varied consequences. Proceedings of the Royal Society of London Series B 277: 1923-1928. 
Wilson RS, James RS, Bywater C & Seebacher F. 2009. Costs and benefits of increased weapon size differ between sexes of the slender crayfish, Cherax dispar. Journal of Experimental Biology 212:853-858.

Bywater C, Angilletta MJ and Wilson RS. 2008. Weapon size is a reliable predictor of weapon strength and social dominance in females of the slender crayfish. Functional Ecology. 22:311-316.

Seebacher F & Wilson RS. 2007. Individual recognition in crayfish (Cherax dispar): the roles of strength and experience in deciding aggressive encounters. Biology Letters 3:471-474. 
Wilson RS, Angilletta MJ, James RS, Navas C & Seebacher F. 2007. Dishonest signals of strength in male slender crayfish (Cherax dispar) during agonistic interactions. The American Naturalist. 170:284-291