Cat-sized rats are causing trouble in the Florida keys. A pack of Gambian giant pouched rats have been breeding in the keys despite officials’ efforts to eradicate them.

NBC Miami reports that Officials are worried about the vermin making it over to the mainland, saying that the hungry species could wipe out crops and upset the delicate ecological balance in Florida.

Scort Hardin, the exotic species coordinator for Florida’s Fish and Wildlife Conservation Commission, said:

“We thought we had them whipped as of 2009…. In the early part of 2011, a resident e-mailed me and said he saw one of the rats. We were skeptical but went back and talked to people and [saw] there were rats that we missed.”

Hardin believes that there are less than two dozen giant rats roaming Grassy Key where they were trapped during multiple efforts last year. The Wildlife Conservation Commission will set out once again this July in an attempt to trap the Gambian giant pouched rats.

Hardin told Keys Net:

“I would not imagine there’s more than another couple of dozen at most. We’ve caught them all within a half-mile of each other… We think they have not moved far but they clearly reproduced.”

MSNBC reports that the cat-sized rats were introduced to the island by a local rat breeder more than a decade ago. The rats have moved into the wild where they are now breeding and wreaking havoc on the ecosystem.

Here’s a video about the giant rats in Florida.