Part 2

By reducing leaf size, the plant minimizes surface through which water can be lost. Green stems assume the task of photosynthesis, normally done by leaves, providing food for the plant of this arid environment.

Although the sand does not often appear wet, pickleweed suggests water is not far below the surface. It requires a wet soil and can grow in very salty areas. Watch for pickleweed near Badwater also.

Find a different shrub, gently rub a leaf and smell it. Does it smell faintly like fish? Look at the leaf you have just rubbed. Did the surface dust rub off to reveal a deeper shade of green? Does it have fleshy leaves? If so, you have found the inkweed (Suaeda torryana). If your shrub has a less noticeable smell, and perhaps rubber-like texture, and if you did not easily remove the white chalky coating from the light gray green leaves, it is saltbush. If your shrub has numerous tiny spines, be careful, you may have found a Russian thistle (Salsola kali) or tumbleweed, as it is also called. They are not native to Death Valley, but have become established in certain areas.

Inkweed’s young succulent leaves and seeds were used for food by local Shoshoni Indians. Stems and leaves were processed to make a black dye. You may notice tiny balls of seeds at the very ends of some branches. The green flowers are very inconspicuous.

Saltbush is light green and its dry, flat leaves are covered with salt. Roots remove salts from the soil and water, then the salt is deposited on the outer surface of the leaves. Consequently, the whitened leaf surfaces reflect sunlight, thereby reducing temperature and water loss. There are male and female saltbushes. You may want to search for seeds or flowers. Seeds on female bushes have four tiny wings which give it the name—four-wing saltbush (Atriplex canescens). Seeds were used as food by Shoshoni Indians.

On your way into the dunes did you notice any other plants? If not, watch for them as you return to your vehicle. Remember, the kinds of plants vary depending on your location in the dunes. The clumps of grass near the picnic tables are alkali sacaton (Sporobolis airoides). Approaching the tall dunes you may have seen large plants with small, shiny, smooth, dark green leaves—the creosote bush (Larrea tridentata). It has small yellow flowers, usually observed in springtime. Later, small, fuzzy, white balls containing seeds grow on its branches. The larger green or brown, walnut shaped growths on the branches are galls formed in response to an insect invader (midge). If you missed creosote bushes in the dunes, watch for them along the roadsides—they are common.

Although the sand dunes seem dry, there is an underground reservoir providing moisture and nutrients for vegetation. The crusty mud playa acts as a cap and reduces evaporation of the underground water supply. Nearby, at Salt Creek, the same water flows on the surface as a stream during the winter and spring.

Most plants grow in the hollows between the dunes where they receive some protection from the wind and can reach water more easily. Yet, the mesquite tree (Prosopis glandulosa), probably the largest plant in sight, is often on top of the dunes. By slowing the wind with its branches, the mesquite causes sand to pile up in mounds beneath it. Sometimes sand completely covers a part of the tree causing branches to die. The sand then blows away, exposing those dead branches. Look for an example which illustrates this sand movement. Mesquite trees have thorns, so be careful. The mesquite tree loses its small, delicate leaves during winter. Its deep root system, growing 50-60 ft. (16-20 m) into the ground to reach fresh water, helps the tree survive. Some plants, such as saltbush, pickleweed, and mesquite seem incompatible because of different mineral and water requirements. However, these plants are able to live near each other because their roots are drawing moisture and nutrients from different levels of the soil. For example, in a rain forest, where the roots have ample water, most plant growth is above ground where competition is for sunlight. Whereas in a desert, where sunlight is abundant, competition for water is more critical. The root system of desert plants are highly developed, and each plant will find the optimum level in the soil suitable for its growth.

Be careful not to trample the roots as you explore the mound of sand near the mesquite tree—you may collapse a burrow—remember, you and the animals may be sharing the same shade.

Mesquite trees are also special in that they produce an edible and nutritious fruit. In late spring, tiny, yellow flower spikes hang from the branches. These develop into yellow bean pods by late summer. Many different animals use the beans for food. Mesquite beans were also a major food source for the Shoshoni.

WHAT DID THE SHOSHONI DO HERE?

Shoshoni Indians have lived in Death Valley for many years—migrating to the mountains for the hot summer months and returning to the valley for the winter. Their movements were related to supplies of food and water and influence of temperature. It is more likely that areas such as these sand dunes were visited for food gathering rather than as a place of residence. To survive in the desert, the Shoshoni had to learn which plants to eat, where they grew and when to harvest them. They also learned which animals were reliable food sources—where they could be found in abundance and when they were active.

Use your imagination—how well could you survive in this wild area? Where and how would you find water? Which plants and animals would you eat?

WHICH ANIMALS LIVE HERE?

Guess which animal lives in which hole! How large is the entrance? The size of the entrance suggests the size of the animal. How many other openings are nearby? Often escape exits save rodents from predators. Are there recent tracks nearby to indicate it is an active burrow, or is it covered with sand and debris blown in by the wind?

Inside these burrows the temperature and living conditions are not as extreme as those on the surface of the sand. Try digging a small hole in the sand well away from bushes. How soon does the sand change as you dig? Is it warmer or cooler or wetter? Beneath the surface the moderate temperatures and increased moisture provide an escape from the intense heat. Consequently, dune residents spend the day in their dens and are active at night.

Kangaroo rats, for example, cannot tolerate heat and escape it by living underground. Also they are active only at night. They are very efficient water conservationists. Although water is essential to the kangaroo rat, they rarely drink, but produce their own water from insects and dry seeds they eat. They have no sweat glands, and excrete highly concentrated wastes to minimize water loss.

These rodents are not related to kangaroos at all! Their name refers to their hind legs which are highly developed for jumping.

Watch for their tracks—when a kangaroo rat is moving slowly, it drags its tail which leaves a trail in the sand in conjunction with its foot prints. When the rat moves quickly, its tail doesn’t drag. From clues such as these we can determine whether the rat is running from a predator or just leisurely looking for food. The entrances to their burrows are about 4-5 in. (10-12 cm) in diameter and may be 3 ft. (1 m) or more deep. Smaller rodents, such as pocket mice, have similar habits but live in smaller burrows.

Lizards are more active during daylight hours. Even though they tolerate higher temperatures than rodents, they would perish if they were stranded in the open sun for an extended period of time. Notice how they run from bush to bush, seeking the protective coolness as well as cover. Lizards are cold-blooded animals, responding to temperatures around them—cold, inactive—warm, active. In the winter months, there is very little lizard activity. However, summer days with ground temperatures reaching 200 degrees F. (92 degrees C.) or more are too hot for lizards, and they must seek shelter. They eat plant material, insects and smaller lizards, obtaining moisture from their food. They also conserve water by excreting highly concentrated waste.

Perhaps least observed, but most inquired about dunes dweller, is the sidewinder. Have you seen evidence of this rattlesnake today? It moves in a sidewise manner leaving a series of parallel, J-shaped tracks in the sand.

By looping across the sand, the sidewinder reduces slippage over the loose material and decreases the amount of body surface in contact with the hot sand. Sidewinders are primarily active at night, and escape the heat of the day under a bush or buried in the sand, exposing only the small horn-like structures on their heads. They eat kangaroo rats, mice and lizards.

Imagine the dunes as an ocean where all the sand is water and plants are islands scattered about. Each island offers shelter and a food supply for the animals. Everytime an animal leaves the security of an island it takes a risk. In daylight, people may play in the sand, but at night the dunes come alive with the real business of survival. Usually all we see of this activity the following morning is the evidence—tracks. Some tracks are easily identified—each tells a story. Use the diagrams to determine which animals most recently crossed the sea of sand around you.

Coyotes come into the dunes for food. True opportunists, they eat whatever is available—mice, kangaroo rats, rabbits, insects, mesquite beans and many other things. Their tracks are difficult to distinguish from those left by domestic dogs. Smaller dog-like tracks are left by the kit fox. These small foxes have large ears and well padded feet. They too feed on small rodents. Coyotes and kit foxes receive moisture from their food and drink water at springs within their hunting range. They avoid exposure to heat by being active at night and staying in dens or shaded areas during the heat of the day.

TRACKS

Jackrabbits are not seen often in the dunes, although their tracks and droppings are seen occasionally. They feed on plants, getting moisture from their food rather than from distant springs. Large ears radiate excess body heat and help cool the animal as it rests in shaded areas during the hot day.

Have you seen any birds? Birds also leave tracks! The large bird tracks here are generally left by ravens—big, black birds which eat almost anything. In the spring and fall, some migrating birds stop briefly. Shrikes, sparrows, kingbirds and blackbirds are among the visitors and residents of the dunes. Insects and vegetation provide food and shelter for them.

Have you seen any insects? Tracks resembling those of a tiny bulldozer tell us where beetles have traveled. Shiny black circus beetles or stinkbugs and gray snout beetles are often seen.