I woke before dawn. The beam of a flashlight pierced my tent. "Bosco," someone said, and there was rustling outside. It was time to find the Hainan gibbon.
I was not well-rested: The ground was hard, and Bosco had snored like a broken muffler. Down by the cabin, the tracking team silently prepared. The plan was to split into two groups. I would head north to the vantage point with Bosco, Jay, Mr. Li No. 4, and another tracking-team member named Mr. Chong; the others would head east. The hike, should take about 60 minutes, though the tracking team had done it in as few as 24.
Mr. Li led the way across the stream. Bosco had said that at the higher altitudes it would be too dry for leeches. Consequently, we had left our leech socks behind. But the mountainside was wet—yesterday's rain still filtered through the forest. In the darkness, you could not be sure if every itch or movement on your body was a bead of dew or sweat or whether a leech had hitched a ride.
Either way, I could not worry too much about the leeches. Mr. Li was fast, and keeping up required concentration. At times, he would disappear completely. I would fumble in the darkness, panic, listen for Bosco and the rest behind me, and then spot the pinprick of his head lamp in the distance. My flashlight reclaimed only a few yards from the blackness, but I could tell from the tug of gravity that we walked along the sides of mountains. The narrow footpaths sometimes gave way, and I clutched at whatever I could to maintain balance—a tree, a vine, a fistful of rotten leaves.
The sun began to dilute the darkness. The path broadened, and there was a long ascent. It went on and on, leveled for a bit, and then went on some more. Eventually, almost at random, we stopped.
The vantage point was not what I had expected. It was tiny, a single pore of dirt on the mountain's forested face. There were no scenic glimpses of other peaks, no sunrises to behold. The vantage was entirely auditory. We would sit there and listen for the gibbons.
Normally, the mating male and female gibbon of each group sing a duet when they wake between 6 a.m. and 7 a.m., and then they might sing a shorter song between 9 and 10. Bosco peeled back his socks and incinerated leeches with his cigarette, while Mr. Li and Mr. Chong began to build a fire. Daylight came, and we heard nothing. At least it wasn't raining. Mr. Chong called the other group on his cell phone at 7. They had only silence to report.
"Mr. Li says that when it's nice like this, sometimes the gibbons don't call until 10," Bosco told me.
The fire crackled, and the logs turned white with ash, as though grown old. Jay disappeared and returned to say that he had discovered four species of orchid on a single log. None was in bloom. The others chatted in Mandarin; Bosco occasionally hummed the theme song to The Godfather. I stared into the canopy. It seemed that, if I just stared at a treetop long enough, a gibbon would appear. But a gibbon had not appeared by 8. I continued staring, but it had not appeared by 9, and it had not appeared by 10.
I felt sick to my stomach. A few days earlier, after I asked Bosco a particularly ignorant question, he said, "You're a naturalist, right?" Well, no, not exactly. I had never really camped outside of my parents' backyard. I arrived in China with expectations of adventure and fresh air, of forests where the orchids flowered and the animals showed up for photos. Though I reminded myself repeatedly that I was unlikely to see the gibbon, I suppose I had not really believed it. With noontime looming, I faced several more hours of tedium and leeches, another night on a hard bed in a sweaty tent, waking up at the same dark hour the next morning and hiking the same dark trail so that I could maybe hear the song of a gibbon that I may or may not eventually see. I was not enjoying the outdoor life, and I was disappointed with myself: I was softer than I had hoped I would be.
For the tracking team, this was routine. The eight men worked in teams of four, and they went into the forest on five-day shifts. Each day, two team members would set out for Group A, and the other two for Group B. They worked from dawn until whenever the gibbons took off for their sleeping trees, usually around 4 in the afternoon. Many of the trackers left families in Bawangling town; nearly all of them had contracted malaria at some point. For them, it was not a matter of adventure or even conservation, though they had come to respect and love the gibbon. It was work. They earned a modest living by Chinese standards—about $100 a month.
Mr. Li and Mr. Chong kept busy by gathering firewood. They tested their strength by breaking logs and stabbed dead leaves with sharpened sticks and roasted them over the flames. At 10:15, Mr. Chong's cell phone rang. The other group had heard a two-to-three-minute song by a male gibbon. Bosco laughed: They weren't too far from base camp, near the point where he had seen his first Hainan gibbon. We set off immediately, descending into a valley and then emerging to find the other team spread across a ridge and looking into the treetops. There was an opening in the canopy with a few naked branches spotlit by the sun. It seemed an appropriate place for a gibbon to appear, and so I fixated on it. A few small creatures leaped across the branches. I borrowed binoculars and took a peek: chipmunks.
We waited for several minutes. Bosco suggested that the song may have been from a solitary male, carrying on his half of the ritual without a partner. "Seeing a lone male is pure chance," Bosco said. His tone suggested, "Don't get your hopes up."
The adrenaline that had overridden my legs' exhaustion began to recede. Then someone hissed at us from up the mountain. We ran to Mr. Li, and he pointed at the trees. Lao Tai Tai—the old female of Group B. Her long, white profile swung through the space between two trees. It was only a second. Then she disappeared into a shroud of leaves. The sighting was too brief for me to take a photo, and I feared that might be it, but a moment later, she climbed onto a higher branch, tucked into a crouch, and rested her chin against her knees.
"She's so slow for a gibbon," Bosco said. "She always gets lost." Two months earlier, the gibbon trackers had seen Group B without her. They sent everyone to find her and, eventually, they watched the mating male of Group B retrieve her. It was probably his call that the other tracking team had heard; he was telling Lao Tai Tai to catch up. If we could keep up with her, she would lead us to the other gibbons.
She was in no hurry. If Lao Tai Tai was lost, she did not seem much distressed: She lounged on branches, scratched her face, and nibbled on fruit. She couldn't have cared less about us. She watched us for a moment but quickly looked away, uninterested. Then she took off overhead, the leaves quivering in her wake.
I asked Bosco why he thought Group B kept Lao Tai Tai around when she slowed everyone down; the gibbons, after all, regularly expelled younger males. He pointed out that most of the group—a sizable chunk of the entire surviving Hainan gibbon population—was her offspring. "Maybe they do have this sense of family bonding," he suggested.
We followed her up the mountainside, tripping over roots and vines, stopping for manic bursts of photos. Bosco said that the rest of Group B was probably within 50 yards. It was past noon now. The sun poked stalactites of light through the canopy. When she neared the peak, Lao Tai Tai began to swing down the other side of the mountain. We pursued, the earth loosening beneath our boots and quickening our descent. We slowed ourselves by grabbing tree trunks or sitting down to ride the little landslides that we caused.
Midway down, Lao Tai Tai hunched on a branch. She moved behind a thicket of twigs and leaves, showing us her back, an arm, her rear while hiding the rest of her body, like a cabaret dancer behind a curtain. Then she leaped forward with her legs tucked beneath her. A tree obscured her flight as she passed behind it, but she emerged on the other side in the most classic of gibbon poses: both hands clutched to an overhead branch, her long body silhouetted by a shard of sky. She looked out across the valley and drank in a view that we terrestrial apes could not enjoy. Releasing one hand, she pirouetted and picked at something in the tree. She reached for branches with her left hand and foot, leaving her right leg dangling like the corner of an awning come undone. She stared right at us. A moment later, she was gone.
We tried to follow her into the valley and up the side of the next mountain. We still had not seen the rest of Group B. We hoisted ourselves up the mountainside, using roots and vines as rungs and clutches. My boots filled with dirt; something stung my hand. It did not matter. Mr. Chong or Mr. Li occasionally pointed upward, but all I would see was shaking leaves. Eventually, Bosco called from beneath me. It was time to go back; Jay had a flight to catch in Haikou. I continued upward for a few more yards and joined Mr. Chong and Mr. Li behind a fallen tree. Lao Tai Tai was above us. I dropped to one knee and snapped as many photos as I could, but when I checked them later, the trees were empty.