Each animal species is adapted to the conditions of its preferred environment. The prairie dog and red squirrel have similar roles in their respective habitats, as do the meadowlark in the grassland, the house wren in the deciduous woodlands, the rock wren on barren slopes, and the brilliant western tanager of the pine forests that is calling “_pit-ik, pit-ik, pit-ik_” from a branch overhead. Whether herbivore, carnivore, scavenger, or decomposer, all of the countless, magnificently varied life-forms of each community share in the endless flow of chemical energy that originates with the touch of sun on chlorophyll. Eagle, prairie dog, bacterium, man—we all owe our lives, directly or indirectly, to the green leaf’s unique ability to convert light energy into chemical energy. So does this colony of black ants foraging near my feet. Back and forth the living lines run, each individual obeying its ancient, perfected legacy of instinct. One carries aloft the bright green corpse of a lacewing. With a little last-minute help from fellow workers, the ant carries its burden down into the nest hole. With its powerful jaws, another ant tugs the brittle remains of a once formidable foe—a jumping spider. So intent is the ant in its labor, it fails to avoid a deadly trap, however. In the soft ground along the margins of the trail is a craterfield of funnel-shaped pits. At the bottom of each, hidden just below the soil, waits quick death in the form of jaws even stronger than the ant’s. These insects, called antlions, are the larval stages of the equally voracious tiger-beetle. Having tipped its load over the rim of the funnel, the ant disengages itself and attempts to crawl up the incline and get to the other side of the spider to pull it out again. But the loose soil particles offer little traction and the ant begins to slip. Frantic, it works its legs faster, making it slide downward more quickly. Alerted now by vibrations from the struggling insect, a hidden antlion waits its moment to strike. When the ant touches bottom, the hooked jaws appear, snapping once, twice, and finally closing shut about the thorax of its prey. In a moment, all is over, the ant dragged beneath the soil at the bottom of the crater. The corpse of the spider, part way down the incline, is occasionally investigated by other passing ants. But the ants at the lip of the trap seem to sense the danger and leave the stranded prize alone. Other antlions, at the bottom of their expertly engineered traps, lie hidden from the passing parade of life above. Obeying their own instinct messages, they need only wait to survive. A disturbance in the dog town starts the animals to barking and scurrying in every direction toward their burrows. Two figures from the campground have appeared up the incline. Their determined stride and the coils of rope at their shoulders suggest that the Tower’s summit may well be explored again today.