|Rat race? Rodent 'Razza' eludes scientists
By Ray Lilley, Associated Press
WELLINGTON, New Zealand — Think your life is a rat race? Just ask
scientists about a rodent named "Razza," who gave a whole new
meaning to the phrase 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 this week's issue
of the journal Nature.
The study was motivated by the need for conservation "because of the
problems of rats on islands and rats reinvading islands that have
been cleared," author Mick Clout of the University of Auckland's
School of Biological Sciences told The Associated Press on Thursday.
"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.
At least 11 New Zealand offshore islands cleared of rodents have
been reinvaded in the past two decades.
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.
During that time, the rat evaded an arsenal of traps and poisoned
baits that included peanut butter. He even continued to stay one
step ahead of sniffer dogs sent in to track him down.
Then he disappeared only to turn up on neighboring Otata Island
after his dip, apparently motivated by primordial urges during the
spring-summer mating season, Clout said.
Researchers believe Razza's island-hopping journey was the longest
confirmed swim by a rat.
"If this had been a pregnant female rat it would have been a
problem," Clout said. "It takes only one ... to establish a
The saga didn't end there. Scientists spent eight more weeks trying
to eliminate the ever-elusive invader on the second island.
"We were literally tearing our hair out at times trying to find this
animal," Clout said.
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 website.
"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
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 scientists have since released another solo male rat with radio
transmitter on the rodent-free 23-acre Motuhoropapa Island to make
sure Razza's race wasn't a fluke.
"We want to check whether this (Razza) was normal behavior," Clout