Skull Rock: a walk from Jumbo Rocks campground

Welcome to Jumbo Rocks, the biggest campground in Joshua Tree National Park, set right in the middle of these giant boulder piles at about forty-four hundred feet.

Long before there was a campground, this was home. The park sits in the traditional homelands of the Serrano, the Chemehuevi and the Cahuilla peoples, and the Mohave used these lands too. People have lived and traveled in this desert for nearly ten thousand years.

Today's walk is the Skull Rock Nature Trail. It's about half a mile from here to Skull Rock, on sand and rock with a few rocky steps, and almost no shade. Watch for the small signs along the way that name the plants as you pass them. There's no cell signal, but this tour works without one. I'll tell you a story at each spot and stay quiet in between.

Here's the trailhead, across from the campground amphitheater. Before we set off, look up, because tonight is a special night to be camping here.

In 2017, Joshua Tree was named an International Dark Sky Park, one of the places on Earth recognized for keeping its night sky truly dark, even though more than twenty million people live within a few hours' drive. On a clear night from right here, you can watch the Milky Way stretch across the sky.

And this weekend has a new moon, so there's no moonlight to wash out the stars. After dark, you may hear or glimpse bats, too. Sixteen kinds of bats come out at night in this park, hunting insects over the rocks.

One campground rule worth knowing: hammocks and slacklines can't be tied to plants here, not even the junipers, so use the rocks or a stand.

Now, head north on the trail, into the boulders.

Look closely at the rocks around you, and you'll start to see those cracks. Straight lines running through the boulders, and gaps between blocks that look almost like they were cut on purpose. The park itself says Jumbo Rocks is one of the best places to see this pattern of cracks.

Here's what happened next. While the blocks were still buried, groundwater seeped into the cracks and slowly turned some of the minerals into clay. The sharp corners rotted away first, so the rectangular blocks gradually became rounded boulders, wrapped in soft clay.

Then, much later, flash floods washed away the ground that covered them. The clay rinsed out, and the rounded boulders were left sitting where they settled, stacked one on top of another, just like the piles you see now. So it wasn't wind that shaped these rocks. It was water, working very slowly, for a very long time.

This trail passes plants you might not expect in a desert: California junipers, single-leaf pinyon pines and a desert oak, all tough enough to live on a few inches of rain a year. Look for the sign that says what a difference a little water makes. Wherever water collects between the rocks, things grow thicker and greener.

And lots of animals live in these boulders, even if you don't see them. Ravens live here all year. Kangaroo rats are some of the most common mammals in the park, hopping around at night. Wood rats build nests in the rock piles, and they're famous for collecting shiny things, so keep an eye on your keys at camp.

The park's most famous resident, the desert tortoise, is a threatened species. This late in the year, tortoises are usually tucked away underground, waiting for spring. If you ever do see one, give it space and never pick it up.

There it is: Skull Rock. Two deep, hollow eye sockets in a huge rounded boulder, staring out at the road.

Nobody carved it. Rainwater did. Over thousands of years, water collected in small dips on the face of the rock and slowly ate into the granite, a little more with every storm, until those dips became the two deep eye sockets you see now. It's the same water story as the rest of these boulders, just with a face.

The road is right here, and drivers are often looking at the rock instead of the road, so keep the kids close. If you scramble on the boulders, go slowly and stay where you can climb back down.

From here you have two choices. Walk back the way you came, about half a mile to camp, past the same signs. Or keep going on the full loop: cross the road at the crosswalk and follow the trail on the other side back toward the campground entrance, about a mile more. You'll cross the road again at the campground entrance, so take care there too, then follow the campground road back. Either way, thanks for walking to Skull Rock with me, and enjoy the stars tonight.