The javelina, or peccary, smells like a skunk. This nighttime wanderer uses the scent for territorial marking, not defense. Curious and shortsighted, javelinas might approach a hiker—not to attack, but to investigate.
Few and far between are the springs with sufficient flow to send a brook singing down a ravine. But such a place is Glenn Spring, the chief spring along a dry draw that starts in the Chisos and cuts deeply through many-colored clays as it crosses the desert. Historic photos show Glenn Spring enclosed within a man-made rock wall. Today you cannot even find the source, so thick is the tangle of tules and cane grown up around it. The flow from Glenn Spring trickles down the draw about 1.5 kilometers (1 mile), collecting in pools and gurgling over rocks before it goes underground. Some of the pools are crystal clear, and some are black with the acids of plant decay. Deeper pools are fern-green with algae. Little black snails harvest algae on the rocks and leopard frogs croak and plop, so quick to hide among the reeds that you can hardly find them. These slim, spotted amphibians, insect feeders, mate in water. Their larval young, free-swimming tadpoles, must live in water, feeding on microscopic organisms until they grow lungs and legs for life ashore.
The tadpole itself falls prey to giant water bugs, air-breathing water dwellers that are also strong fliers. The water boatman is a vegetarian who sculls about from one underwater plant to another. You can hardly tell him from the backswimmer except that the latter swings his oars upside down and spends much time on the surface hanging head down, the better to spy the aquatic insects upon which he feeds. The water strider is another hunter, but this spider-legged semi-aquatic skates atop the water, seeking terrestrial insects that have dropped onto the surface. Just as the birds and bats eat different foods at different feeding levels, so do the creatures that inhabit a pool, be it only centimeters deep.
And the creatures above the pool: The damselfly alights on a reed and rests with its transparent, netlike wings closed above its slim body. The stouter-bodied dragonfly rests with its wings outstretched and likes to fly in tandem. Both of these aerial beauties must lay their eggs in water, and their larvae are fully aquatic predators that breathe with gills like fish.
This flash flood (above) washed out a portion of the Maverick Road. Flash floods can be killers to the unwary. They can sweep down on you from storms you never saw or heard.
Cottonwood Creek’s wide bed suggests that it, too, knows rage. Low water levels favor algae growths whose colors mirror the cottonwoods’ refreshing verdure overhead.
Many of the same water insects inhabit yet another type of waterhole, the tinaja, a natural pothole that traps rain or runoff in solid rock. Dependent on rainfall, tinajas often dry up, yet they may be the only water source over a large area. If a tinaja is deep enough it may survive evaporation, but the water may shrink back so far below the lip of the bowl that animals cannot reach it. A cougar once drowned in a tinaja here because it could not climb out again. Tinajas may also turn into death traps for the plants and insects that inhabit them. In a well-balanced pool the algae create the oxygen and food that aquatic creatures need, but as the pool dries up there is less and less oxygen and the products of decay become concentrated. At last these become so poisonous that the reproductive engine cuts off and the pool is literally dead. But even a dead pool may be a source of life to outside animals.
Ernst Tinaja is a good site for watching desert wildlife. It lies in a rocky, canyon-like drainage near the Old Ore Road. Though the upper tank measures 6 by 9 meters (20 by 30 feet) animals may not be able to use it because when the water is 3 meters (10 feet) deep it lies more than one-half meter (2 feet) below the edge. But mule deer and javelina frequent the smaller pools, which likely hold algae and a roster of aquatic life.