This desert-like park is a haven for native cats such as puma and yagouaroundi. You can easily spot armadillo, guanaco, mara (Patagonian hare) and vizcacha, while birdlife includes the rhea-like ñandú and many birds of prey such as the carancho (crested caracara). Though you’re unlikely to encounter them unless you overturn rocks, be aware of the highly poisonous pit vipers commonly known as yarará.
The most rewarding hike in the area is the hour-long climb to the 589m peak Cerro de la Sociedad Científica Argentina; watch for flowering cacti such as Trichocereus candicans between boulders. From the summit there are outstanding views of the entire sierra and surrounding marshes and salt lakes.
About 10km by car from the visitors center is the Casona, the ruins of the old house of former Estancia Santa María. Another 2km further along, the road peters out at the parking lot for the Valle de las Pinturas, where a 600m trail leads down a rock-strewn valley to some petroglyphs.
These same two attractions are accessible to walkers via a 9km footpath from the visitors center.
More information is available at the visitors center (open 8am to 6pm). Spring, when flowers are blooming and the temperatures aren’t too hot, is the best time to visit the park.