A number of birds live in the area surrounding the cave complex, including the golden eagle, short-toed snake eagle, Egyptian vulture, Eurasian sparrowhawk, Eurasian eagle-owl, griffon vulture, tawny owl, and the peregrine falcon.
Inside the caves there are several species of bats, such as the cave bat, greater horseshoe bat, lesser horseshoe bat, and Geoffroy's bat.
Other mammal species that live in the region include the Pyrenean desman, wildcat, dormouse or the Eurasian otter.

In 2012, a paper was released documenting the presence of 187 invertebrate species in Ojo Guareña, belonging to a variety of phyla.
32 of them were entirely new to science.
Of the more than 200 cave-dwelling aquatic invertebrates that are known in Spain, more than a quarter of them were discovered in Ojo Guareña.

The vegetation in the Ojo Guareña area is very diverse due to its location in a transition zone between the Mediterranean and Euro-siberian climate regions.
The surface of the natural monument is occupied by meadows, grasslands, heathlands and Iberian forests.
A number of types of trees are found in these forested areas, including multiple varieties of oak, beech, hazel, poplar, alder, pine, and aspen.
A number of birds live in the area surrounding the cave complex, including the golden eagle, short-toed snake eagle, Egyptian vulture, Eurasian sparrowhawk, Eurasian eagle-owl, griffon vulture, tawny owl, and the peregrine falcon. Inside the caves there are several species of bats, such as the cave bat, greater horseshoe bat, lesser horseshoe bat, and Geoffroy's bat. Other mammal species that live in the region include the Pyrenean desman, wildcat, dormouse or the Eurasian otter.
In 2012, a paper was released documenting the presence of 187 invertebrate species in Ojo Guareña, belonging to a variety of phyla. 32 of them were entirely new to science. Of the more than 200 cave-dwelling aquatic invertebrates that are known in Spain, more than a quarter of them were discovered in Ojo Guareña.
The vegetation in the Ojo Guareña area is very diverse due to its location in a transition zone between the Mediterranean and Euro-siberian climate regions. The surface of the natural monument is occupied by meadows, grasslands, heathlands and Iberian forests. A number of types of trees are found in these forested areas, including multiple varieties of oak, beech, hazel, poplar, alder, pine, and aspen.
Ojo Guareña