Nicknamed the “ecosystem engineer,” the beaver (Castor fiber) is one of the keystone species of the ecosystem. After being extinct for over a century in Romania, 182 beavers were reintroduced into the wild between 1998 and 2003. As a species protected under the Habitats Directive, the population has recovered spectacularly, and today, we can say that it is stable and viable in Romania. The most recent observations made by Rewilding Romania field teams show the presence of the beaver in the upper basin of the Timiș River, in the commune of Teregova, Caras-Severin county, and on the Strei River, in the commune of Bretea Română, Hunedoara county. These observations are the first in the above-mentioned areas and show that the species is expanding its territory.