These animals are introduced (descendants of escapees from farms raising animals for fur) and are classified as vermin (nuisable in French). The Brenne park authorities are quietly trapping and removing them, as they are threatening the survival of the endangered Large Copper butterfly because they eat the caterpillars' food plant. Local gardeners often set traps at riverbank exit points to potagers (vegetable gardens) eg at the convent at St Michel en Brenne, as Coypu destroy the crops. There is a small trade in Coypu meat locally, with the regional produce shops at La Gabrière and the Maison du Nature in the Brenne selling jars of pâté de ragondin.
Coypu are easy to mistake at first glance for Beaver, as they are both large aquatic rodents. A large Coypu could weigh 10 kg and be a metre long.
They are completely vegetarian. Unfortunately they favour plants such as Water Dock, which is the caterpillar host plant for the rare Large Copper butterfly, and Coypu have caused the disappearance of both the plant and the butterfly from a number of areas in the Brenne. They also cause damage to waterlilies, which can be a problem for Whiskered Terns (who nest on the floating leaves), ducks, grebes and certain dragonflies.
A Coypu swims across an étang in the Brenne