Look in the Rocks for Desert Critters

The beam of sunlight reflecting off my mirror penetrated the rock crevice like a laser, slicing along the stony gap until it found a tiny, vaguely annoyed face blinking at the light-a banded gecko, one of the Southwest's most common lizards, safe in its cozy fissure.

The gecko and I shared a moment in the vast, tumbled boulder fields along the road to Four Peaks, relics of Arizona's volcanic past. These peaks in the Mazatzal Mountains are quintessential Sonoran Desert. High enough to receive extra rain and even snow, the stony slopes harbor saguaros, desert plants and animal life. On that day, the mountain's frosted flanks attested to a wet winter. Like an echo of Africa's Mount Kilimanjaro, those distant white summits provided a backdrop for the sculpted vistas of the boulder fields. Their bounty of snow would be released slowly as meltwater, charging normally dry washes and springs for months to come.

My wife and I had come for a hike and a leisurely search for some of the lesser-known creatures of the rocky slopes. In particular, I hoped to see a night lizard, one of Arizona's neatest little reptiles.

The open stretches of ground between outcrops were carpeted with wildflowers, for the season to search for night lizards is early spring-March and April. This was a good year, balmy days following a wet winter, and the flowers were thick. It was difficult to gain the next rock pile without crushing any blooms. Once there, my wife, a veteran in the outdoors and an occasional rock climber, had no difficulty navigating the sloping granite faces. I was less graceful, but mercifully, there were no other witnesses. Scrambling over the boulders, we inspected likely looking crevices by reflecting sunlight off a small mechanic's mirror, angling the beam along the gaps in the stone until we located something-a technique known as “crevicing” among its practitioners. As an outdoor pastime, crevicing is one of the most benign and user-friendly activi-ties. There is a slight challenge in learning to control the reflected beam of light-a technique quickly mastered that can bring a sense of achievement, especially for children. The creatures encountered by inspecting the boulder crevices are always fascinat-ing and well out of reach-safe from being molested by observers. If a crevice-dweller decides it doesn't like the light, it can van-ish into the depths and no harm is done. There's an almost obsessive fascination with searching crevices during favorable seasons. It's something like gambling-one is sure that the next crevice will pay off. In one crevice, a chuckwalla lizard stared back at me with an expression that sug-gested ancient wisdom.

The boulder surfaces are as sterile a hab-itat as can be found. Splashed with solar radiation, devoid of any cover, open to the drying winds, the bare rock faces are visited by day only by the most durable wildlife, including lizards and a few tough bugs. The environment in the crevices is much more attractive. Windblown soil and dead vegetation collect in the depths, holding moisture, giving cover and rooting plants. Older outcrops can be so fractured that the habitable volume exceeds the uninhabitable area of the surface. The crevices are thousands of years old, and some of the deeper ones have spring water flowing at their bottoms. Many interconnect-a freeway system leading everywhere in the outcrops, safe from the inhospitable surface, and full of life. Strange, flat selenopid crab spiders hug the boulder faces, their color and texture perfectly matching their surroundings. Their relatives, the giant crab spiders, are not so bold. Round and furry, they stretch silk chambers between the sides of the cracks. Bizarre tailless whipscorpions, deliberate and graceful, creep silently through the shadowy world at the heart of the ancient stones. Bark scorpions pack themselves into narrow gaps, waiting for night to forage on the surface. Giant centipedes press their 8-inch bodies through tight spaces, eating anything smaller than themselves. Relics of quieter dramas can be found among the boulders. On another trip one cold spring day, I moved a loose capstone and found some hibernating lizards. All the way at the back of the stone pocket lay the remains of a mummified lizard that had gone to sleep for the winter and never woke up. In the dry desert climate, decay is slow, and the tiny skeleton might have dated back several years. Snakes nosing through the cracks would welcome a meal of a sleeping lizard. In the world of the crevice-dwellers, danger comes from below, and for an unwary liz-ard, that slithering might be the last sound it hears. There are ways to evade enemies, though, and somewhere between the ser-pent's mouth and the killing sun, there's a life to be had, and not a bad one at that if you're a night lizard. Adapted to life among the boulders, night lizards live primarily in rock fissures. They measure only about 3 inches long, but they have it made. At midday, when shafts of light penetrate deep into the fissures, they can bask in full sun while remaining secure in a vertical crevice. They feed on small insects that inhabit the crevices and don't even have to leave home to get groceries. They do have to watch out for snakes and other enemies in the crevices but, unlike prey animals in other habitats whose cover can be moved by a strong attacker, the stony retreats of night lizards are impervious to bears, birds and people. Those snakes are a problem, though. One in particular is a slender, graceful serpent modestly dressed in shades of gray, and dedicated to eating lizards-the Sonoran lyre snake. Lyre snakes are rear-fanged and mildly venomous. They feed almost exclusively on lizards. If they secure a hold anywhere on a lizard, they work their mouths onto the victim until they make contact with their enlarged rear teeth. The deep punc-tures those teeth make are the pathway for a paralyzing venom, and soon the lizard's body goes limp. Lyre snakes almost never fail after they've made a bite. Hatchling lyre snakes are so small they almost have to feed on tiny lizards like night lizards, and the ancient drama of quest and evasion pro-ceeds below our feet, silent and unseen. We found our night lizards and more that day and made it back to the car as the sunset gilded the boulders, highlighting the saguaros against the lengthening shadows. I took a last look back at the slopes, feeling that I had been granted a rare gift-a glimpse of the secret lives of fellow travelers on our little green planet.

It's something like gambling-one is sure that the next crevice will pay off.

Populated with myriad creatures wondrous and terrible, pulsing with rhythms of survival and passage, the world of the crevice-dwellers is so near-inches from our noses as we peer in-and yet beyond our reach. The fortress of stone keeps us out and may shelter some of its secrets forever, but we can still take a peek at the worlds within worlds. All it takes is curiosity-and a beam of light. All