Washington, Nov 14 : A new study has found that when trying to flee their predators, cockroaches choose, seemingly at random, one of a handful of preferred escape routes, leaving their enemies 'guessing'.
Italian researchers studying animal escape responses found that roaches opt for one of a number of possible trajectories.
"By using one of a number of possible trajectories, we think that cockroaches may behave with sufficient unpredictability to avoid the possibility that predators will learn their escape strategy," said Paolo Domenici of CNR-IAMC in Italy.
"As we say in our report, the predator is made to guess," Domenici added.
While the insects don't run away in random directions, they nonetheless didn't seem to flee in an easily predictable manner either.
In the new study, the researchers searched for some pattern by repeatedly testing cockroaches as they escaped from threats.
They found that cockroaches select one of a number of preferred trajectories.
Their choice is not completely random because the angle at which the bugs are stimulated to run seems to limit the options.
However, when they are startled from certain directions-head on, for example-cockroaches flee along four primary escape routes at fixed angles from the threat.
Domenici said that the insects most often choose an escape path directed at a 90 to 180 degree angle from the attack
But it is still unclear exactly how the cockroaches manage this at the neural level.
The results show that "unpredictable" behavioural patterns in nature can actually be quite structured, Domenici said.
Animals that may seem to be carrying out a single behaviour pattern with wide variation could instead be choosing between multiple strategies.
The report is published in Current Biology, a Cell Press publication.