With their solitary and nocturnal habits, you may have some luck spotting foxes, wolves, wild boars, weasels, skunks and salamanders. Rabbits and hares are easier to spot. In the sky you can also easily spot the eagle, the kite and a huge variety of butterfly species. At night, you can hear the hooting of the barn owl, owls and, at the height of the brama (September/October), the deer that were reintroduced to the Lousã Mountains in the 1990s as part of a project run by the University of Aveiro, and their population has increased at a good rate to the point where they are already a major tourist attraction in the region.

The forest was once dominated by native species such as chestnut, oak, cork oak, holly and heather, with the presence of some cultivated species such as cherry.
Currently, there is a large presence of maritime pine and exotic and invasive species such as eucalyptus and mimosas. Even so, the predominant colour is the light green of the chestnut trees, maintaining the unique essence of this mountainous region crossed by the Pena creek.