Officials now fear the nutria as big as a cat, with a long rat's tail and the webbed rear feet of a duck poses a threat to Thailand's lush, rice growing wetlands. When they're free, nutria use their 2.5 centimeter long, bright orange, beaver lke teeth to dig up roots and burrow deeply into the ground. Agriculture officials fear disillusioned nutria ranchers will set their stock loose and put the ecosystem at risk.