One afternoon, returning from a hot, wet slog, vines along the trail tripped me up, and my right knee landed on a small rock. Back home in New England, where rocks come in rounder forms, I would have walked away with a bruise. But this was tsingy in miniature. A barb of limestone drove in nearly to the bone. It took two days to reach a hospital, where a nurse removed dirt from the wound. "Why were you doing this?" she asked, twisting a swab deep into the hole. She looked up. I was sweating. "I think you are a little dumb," she said. The tsingy is the perfect foil to human ambition.
The unusual formations here are a type of karst system, a landscape formed from porous limestone that was dissolved, scoured, and shaped by water. The exact processes that carved such an otherworldly stonescape are complex and rare; only a few similar karst formations exist outside Madagascar. Researchers believe that groundwater infiltrated the great limestone beds and began to dissolve them along joints and faults, creating caves and tunnels. The cavities grew, and eventually their roofs collapsed along the same joints, creating line-straight canyons called grikes, up to 400 feet deep and edged by spires of standing rock. Some grikes are so tight that a human traveler has difficulty passing through them; others are as wide as an avenue.
Observing the tsingy from the air, pilots have been reminded of the deep urban canyons of Manhattan, where an angular, chaotic skyline descends into a grid of streets and alleys, buildings and parks, everything underlain by a circulatory system of pipes, sewers, and train tunnels. The metaphor applies to the tsingy's inhabitants as well, because the formations have become like rows of high-rise apartment buildings, providing shelter to a different array of species at each level.
At the highest reaches there is little soil and no shelter from the sun. Here temperatures often bake above 90°F, and plant and animal life is restricted to creatures that can resist desiccation or move between the pinnacles and the canyons. Lemurs like the white-furred Decken's sifaka and the brown lemur use the tsingy as a kind of highway, leaping from spire to spire as they travel between fruit trees. In slots and crevices lizards chase insects through gardens of drought-tolerant xerophytes—euphorbias, aloes, spine-covered Pachypodium, and other plants that drop long, cablelike roots into the rock searching for water.
In the middle ranges of the high-rise, more niches appear in the canyon walls. Large fruit bats and dark vasa parrots roost here, their cackles and cries echoing through vaulted chambers and crumbling galleries. In shadier spots, bees anchor their nests in holes in the stone.