Mapping a tiny but ruthless killer

May 17th, 2008 - 3:45 pm ICT by admin  

London, May 17 (IANS) Don’t go by its size. The Etruscan shrew, one of tiniest known mammals that weighs just two grams, ranks among the quickest, most ruthless and adaptive predators. It overcomes starvation by feeding twice its weight of crickets, cockroaches and spiders daily, preys that are nearly its size. Hence the attacks have to be quick as a flash.

“The Etruscan shrews trust in their sense of touch and the tactile shape recognition to an extent we do not know from other animal species,” said Michael Brecht of Bernstein Centre in Berlin.

“Etruscan shrew scans its prey and adapts, when necessary, its hunting strategy,” all of which takes a split second. “Thus no prey escapes,” explained Brecht.

Etruscan shrews hunt after sundown, relying on their sense of touch. Their long whiskers help them locate prey and recognise whom exactly they are facing.

They then kill their prey using directed attacks. The researchers could observe that they track down crickets with a forceful bite in the back.

To probe whether the animals recognise their prey by its shape, they offered the shrews a plastic cricket. Though the replica neither moved nor smelled, shrews attacked the plastic prey 15 times.

“Also, the animals can adjust quickly to new situations,” Brecht pointed out. Scientists exchanged the living crickets with a giant cockroach, whose back is well protected by a heavy shield from the attacks of Etruscan shrews.

However, the experiments showed that these nocturnal hunters succeeded in adapting their hunting strategy. Quickly, they figured out that cockroach’s belly is its weak point and make a killing.

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