The Apennine brown bear — the Marsican subspecies — is the symbol of Abruzzo, Lazio and Molise National Park and the primary reason many visitors come to Pescasseroli. With fewer than 60 individuals in the wild, a sighting is never guaranteed, but the park's bears are habituated to a degree of human presence and sightings are reasonably common. Dawn and dusk near the valley meadows give the best odds; the park authority can direct you to current hotspot areas and offers guided wildlife excursions.
The park is also home to the Apennine wolf (here before the bears became the park's emblem), the Apennine chamois (a chamois subspecies reintroduced here after near-extinction), red deer, roe deer, wild boar, and golden eagle. The marked trail network from Pescasseroli is well maintained. The classic bear habitat walk is the Valle di Opi route, a relatively easy half-day circuit through beech forest and open meadow.