Aussie yabbies don't forget their enemy's face

Washington, February 29 : Australian yabbies do not forget the face of their enemies, say researchers.

Zoologists in the Department of Zoology, the University of Melbourne, say that their finding is based on a study on a two-year study that involved over 100 pairs of yabbies.

Writing about their findings in the PLoS ONE journal, they revealed that the species Cherax destructor is capable of facial recognition of individuals, particularly its opponents.

"This is a remarkable capacity for the invertebrate species of yabbies and freshwater crayfish. This is an ability known in humans and some vertebrates but in only a handful of invertebrate species," said Professor David MacMillan, Head of the Department of Zoology who has led the research.

"Yabbies usually fight when they meet. It is as much a way of meeting each other as a way of establishing territory," he added.

According to Professor Macmillan, understanding how simple nervous systems recognise features may prove helpful in developing feature recognition in robots.

During the study, the research team isolated the loser yabby after a fight, and later gave it a choice between its opponent and another crayfish not involved in the fight.

The researchers saw the loser yabby moving towards the opponent it had earlier fought with rather than the crayfish, suggesting that it was capable of visual identity, not just an acute sense of smell.

"Careful observation by our team showed that the facial region is the important area for recognition of yabbies during and after a fight. In particular we showed highly variable cues are used such as colour and face width," Professor Macmillan said.

The research team also tested whether it was possible to engineer false identifications, and whether animals could distinguish between twin opponents.

"We continue to find the yabby is capable of more than we expected for an animal with such a simple nervous system and an invertebrate. Yabbies remember the smell of other crayfish but the extent to which they remember visual features has previously been unknown," Professor Macmillan said.

ANI