Following in the footsteps of the beaver sometimes resembles an expedition. But quickly, the first clues appear. Teeth marks are visible on a tree cut last night. A few kilometers away, a spectacular dam over 20 meters diverts the river, granting a succession of small basins. All of this is the work of a single family: the beavers have transformed the landscape to settle there and the technique is well established. “He consumes the bark and he will plant a whole series of branches in the direction of the current. Then once, he has all this pile of branches and well behind, he will put clay which will make the dam waterproof “. These builders are not easy to see. They only come out in the evening and prefer to be underwater often. Patrick knows a few things about it. Three years, he prepares a documentary. The director knows it, you have to be very patient. “When you see one, therefore, the heart beats a lot more. You have to stay calm, otherwise you miss the shot”. Hunted for its fur, the animal had almost disappeared by the beginning of the 20th century. Protected since 1969, the population keeps growing and they love Belgium. There are more than 2,000 beavers at nearly 400 sites, with some environmental benefits. “Cutting the trees brings light into the river and it develops the whole food chain”. Dams also have a hydrological role. “All the water, which is retained and diverted by the dams, does not end up in the villages to contribute to the phenomenon of flooding”. Beavers have not been spared by the unprecedented floods in Belgium. Three babies were collected in this wildlife protection center. Bottle-fed for several months, they are now in great shape and will be able to go out in the spring. “As these are animals that feed mainly on bark, buds and leaves, we have to wait until spring for them to be enough”. They only have a few weeks left to return to nature and finally live a real life as beavers. TF1 | Report M. Dupont, C. Nieulac