NPS Photo Dale Dombrowski
A tinaja is a bedrock depression that fills with water during the summer monsoonal rains and when snowfall accumulates in the winter. These microhabitats spring to life when the baked-dry stone basins fill with seasonal water. Many of the organisms that live in tinajas, such as crustaceans like fairy shrimp, are known as "drought tolerators" that lay eggs that are able to lose more than 90 percent of their internal water as they lie dormant in the dusty pool bottoms. When water fills the depression again they re-hydrate, hatch, and their life cycle continues. Most tinaja dwellers have very short lives - some as short as 10 days before they lay their eggs and the pool dries up.