We rest after a day of strenuous hiking and listen as one of our guides, Maria, sings a Spanish song while she molds maize tortillas. She places them on a rusty sheet of iron atop small adobe mounds that resemble mini Maya ruins. Wood embers glow underneath.

As darkness descends upon the Maya Biosphere Reserve here in Guatemala’s northernmost region of El Petén, the song of insects and critters fills the air of this intact tropical rain forest.

Sixty-year-old José, our other trail guide, smiles toothlessly and leans his head against a rock pillow for a rare rest, after leading our group of three through this muddy lowland jungle with the agility of a wildcat. Soon, he tends to three pack horses and two saddled horses, before pitching tents to bed down for the night. The riding horses serve as emergency relief in the event of injury or simple exhaustion.

The group contends with “mucho lodo” (lots of mud) while trekking through the jungle.

My wife Mare and I, along with brother-in-law Mike, had to dig down deep for strength. After seven straight hours of hiking through mostly knee-deep mud, we learned to either keep moving or sink. Deep in the jungle we have no communication with the outside world.

Nobody has a cell phone or GPS (Global Positioning System) receiver. A nine-hour day of mudding tomorrow promises to bring us to the ancient metropolis of El Mirador, where we will explore the unexcavated ruins believed to be the highest pyramids in Mesoamerica — El Tigre (180 feet; 55 m) and La Danta (236 feet; 72 m).

Initially we had planned to spend time on the numerous one- or two-day excursions available throughout the Northern Péten area. However, a guidebook passage challenged us, noting that the trek to El Mirador was “not for the faint of heart,” with “rudimentary conditions” (no toilets, beds, no cold beverages in the humid heat); relentless biting insects; and knee-deep mud; yet it was mentioned as an “unforgettable journey.”

It sounded like a good idea at the time, but now we feel that we might be in over our heads.

Maria and José stopped chicle farming several years ago to work as local guides. We met them in their small village of Carmelita, close to the Mexican border. Carmelita is one of the main local gateway communities and our departure point for the organized five-day hike through about 20 miles (32 km) of uninterrupted jungle to El Mirador.

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The Global Heritage Fund is trying to protect 525,100 acres (2,125 km²) of rain forest as an Archaeological and Wildlife Preserve in the heart of the Maya Biosphere from logging and looting, in part by making it more lucrative for locals to work as guides rather than to extract chicle, resin used for making chewing gum, from chicozapote trees.

According to the World Wildlife Fund, the entire Maya Biosphere Reserve, a nature reserve about twice the size of Yellowstone National Park, has lost 70 percent of its forests in the last 10 years. Securing UNESCO World Heritage designation for the area is another goal.

At camp, José tells me a long tale in Spanish. Our guides speak Spanish only, and I speak Spanish like Tarzan. We laugh together, slap each other on the shoulder, hug and kiss cheeks and form a nonverbal bond, instead.

We laugh while moving gingerly on sore legs under a palm-thatched shelter. Maria hands us fresh tortillas wrapped around left-over lunch baloney and scrambled eggs. She laughs with us.

Sweaty, stinky and sticky, Mare and I retire for the night on a thin foam roll inside a small tent. Howler monkeys rummage around the campsite. It’s too hot to sleep and too dark and scary outside the tent. A cool rain soothes us into slumber at around 2 a.m. in the morning.

The 6 a.m. wake-up call comes quickly. Little things, like brushing your teeth, become quite a chore when using water sparingly. It strikes me as an irony to haul water into the rain forest.