Over the years state agriculture officials have dealt with various exotic animals that have been found in the wild, from iguanas to parrots.

But recently they ran into an unusual situation in Nu'uanu: feral guinea pigs.

Agriculture officials have caught 40 wild guinea pigs on four residential neighboring properties on the mauka side of Pu'iwa Street since a resident first reported the animals May 22, said Domingo Cravalho Jr., inspection and compliance section chief for the agriculture department's plant quarantine branch. A resident's cat killed at least another half-dozen, the department said.

"This is one of the more unusual ones," Cravalho said of the guinea pig reports. "We've had reports of rabbits running around, and had to capture those. But I can't recall guinea pigs ever being out and about running around. It's a very different situation."

Officials continued to catch some through last week, although the number of captured guinea pigs has declined, Cravalho said. Nine traps still remain among three of the homes, and officials are looking at expanding their surveillance to include about four more homes, he said.

It's believed that this population of guinea pigs — among the animals allowed to be imported into the state under a permit — is the result of pets (or perhaps one pregnant pet) escaping or being released.

Cravalho urged pet owners to ensure their animals are properly maintained and contained and to hand over any unwanted pets to the nearest humane society. The agriculture department will also accept exotic animals and extend amnesty to those who turn in illegal animals, he said.

"The lesson to be learned is that ... owners should be responsible in maintaining animals in a way that it does not escape into the environment," he said.

"A lot of times when these pets are released, you won't know until populations are built up what impacts it has on the environment."

Non-native animals released into the wild could cause environmental and agricultural damage in Hawai'i, state agriculture officials said.

"Many pet species can become invasive," said Janelle Saneishi, spokeswoman for the state Department of Agriculture. "You would think that guinea pigs are harmless, but they can get invasive if they are allowed to populate in the wild."

Some homeowners have complained that the guinea pigs have eaten ti leaves and other plants in their yards.

Some of the captured guinea pigs were taken to the Hawaiian Humane Society, while others were adopted by quarantine station visitors and others who were aware of the captures, Cravalho said.