While wildlife-watching underground in the park's caverns, you’ll have the chance to see such fun-loving creatures as bats, albino salamanders, blind fish and a variety of squiggly invertebrates. On the surface, howler and white-faced monkeys, armadillos, pizotes (coatis), kinkajous and white-tailed deer are regularly spotted, as are striped hog-nosed skunks and anteaters.
The Barra Honda hills have a few well-marked hiking trails through deciduous, dry tropical forest. Before or after visiting the cave, you can hike 3.5km to the top of Cerro Barra Honda, which has a mirador (lookout point) with a view of Río Tempisque and Golfo de Nicoya. You won't need a guide to hike the trails.