SYDNEY - Among animals, many species seem to slip naturally into their dominant role while others resign themselves to play the part of lowly subordinates. But why do the latter embrace this fate so readily instead of putting up a fight?

A University of Sydney (U-S) team is trying to answer this question by studying the interactions between male mosquito fish to see if their behavioural strategy can be traced to their physical skills.

When the speed of escape in response to an attack was measured, the researchers found that subordinate fish were significantly faster than the dominant ones.

“This is particularly interesting because we predicted the opposite: that dominant fish were the ones that would prove to be more athletic,” explains Frank Seebacher, who led the research team.

“Our data indicate either that there may be a training effect because subordinate fish have to escape quickly and often, or that slower fish become more aggressive because they cannot manoeuvre quickly.”

The researchers also analysed whether damage to the tail and fins may affect the social position of a given individual, and found that, indeed, aggressive behaviours tend to decline as fin damage sustained in fights accumulates.

In other words: if a male has to fight too often to maintain his dominant status, he will probably end up losing it in the end, said a U-S release.

These results were presented at the Society of Experimental Biology annual meeting in Glasgow (UK) on Sunday.