WELLINGTON, New Zealand -- A rodent named "Razza" gave a whole new meaning to the phrase "rat rac... A real rat race...

WELLINGTON, New Zealand -- A rodent named "Razza" gave a whole new meaning to the phrase "rat race" during a four-month chase across two deserted islands in New Zealand.

Like a furry Robinson Crusoe, the brown Norwegian rat was cast away and left to fend for himself in an experiment New Zealand researchers say has given insight into why it's so hard to eradicate vermin from fragile island ecosystems.

For 18 weeks, Razza sidestepped countless traps and turned up his nose at poisoned bait before eventually plunging into the South Pacific and paddling 400 yards in open water to a new island in search of love, according to research published in the journal "Nature."

"We wanted to test how difficult it would be to catch a single rodent using the standard methods of elimination (used for) for higher density populations," he said.

Despite being weighed down by a tiny radio transmitter collar, Razza eluded intensive efforts to trap him during his 10-week sojourn on New Zealand's uninhabited and forested Motuhoropapa Island.

New Zealand Department of Conservation scientist David Towns said the findings raise a series of issues over trying to protect threatened species on predator-free offshore sanctuaries.

The country's indigenous plants and animals often have ineffective defense mechanisms to ward off newly introduced species. Rats and possums have wreaked havoc on some islands.

New Zealand conservationists are using one rodent-free island to establish a colony of highly endangered plump and flightless green parrots called kakapos, according to the department's Web site.

"We didn't know it would be this difficult to trap (one) rat," Towns said, adding that rat-sniffing dogs ended up being the key to Razza's demise.

Only after they picked up the trail was the research team able to saturate the area with traps. The lure of fresh penguin meat was finally what ended Razza's 18 weeks on the lam -- he was killed in the trap.

The scientists have since released another solo male rat on the rodent-free 23-acre Motuhoropapa Island to make sure Razza's race wasn't a fluke.

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