[Illustration: Desert flowering plants adorn a mudflat almost as metaphors of patience. The secret lies with seeds that have adapted to remain dormant for years, if necessary, until enough rain falls to bypass their germination inhibitors.] [Illustration: When rains raise the water level, animals drink from natural tanks such as Ernst Tinaja. Tinajas can also be death traps when the water level falls so low that animals can’t climb back out. Mountain lion claws have etched desperation into the rims of some.] Waterholes, Springs, and the Fifth Season One of the most astonishing sounds in the desert is that of trickling water. One of the happiest desert sights is a pool dancing with aquatic creatures. Who can believe it: Tadpoles darting about, water striders dimpling the surface, blue darners stitching zig-zags through the air and dipping the tips of their abdomens into the water? What a celebration of life in the midst of apparent lifelessness. Water is the single most important need of almost all life forms in the desert. The larger mammals, many birds, and some insects must drink daily to survive. Some amphibians and arthropods must spend at least part of their lives in the water. Each waterhole is a little oasis supporting its community of plants and animals, and drawing from the outside world a thirsty parade of creatures that comes to it to sustain life. Apart from the river, there are at least 180 springs, seeps, and wells in the park that serve as wildlife watering places. Most of these are springs located within the grasslands on the lower slopes of the Chisos Mountains. Springs differ greatly, ranging from a seep with 0.5 centimeters (0.25 inches) of water standing in the grass, to a 25-centimeter (10-inch) deep pool the size of a table top, to a string of pools connected by a flowing stream. Since springs depend for their flow on water seeping through the ground, and since this in turn depends on rainfall, the amount of water found at a spring may vary greatly from season to season and from year to year. Other crucial factors are evaporation and the water consumption and retention properties of the spring’s plant life. You can see most springs a long way off. They stand out like timbered islands in an ocean, with tall cottonwoods, willows, and honey mesquite, and man-high thickets of thorny acacia festooned in silver showers of virgin’s bower. Dozens of little rodent holes perforate the ground among the roots and the tall grasses quiver with furtive comings and goings. Life at such a spring follows a regular pattern from dawn to dusk, although it may actually be busiest at night when most desert creatures are abroad.