Living on a Razor's Edge

The lizard moved in frightened rhythms across the sun-blasted stone. A few quick steps, a turn of its boxy head. Then the stillness, the absolute zero, of a creature that sensed it was being hunted. All around, jagged spires and flutes rose like the towers of some Gothic cathedral, silent and empty. From the canyons below, a parrot flew squawking, breaking the trance. The lizard launched. Hery Rakotondravony's arm fired out. Moments later the young herpetologist uncurled his fingers.

"I think this is a new species."

In the few days we'd spent in Madagascar's Tsingy de Bemaraha national park and reserve, it was the second or third time he'd said this. On an island famous for its biodiversity (90 percent of the species here are endemic, found nowhere else on Earth), the 600-square-mile protected area is an island unto itself, a kind of biofortress, rugged, largely unexplored, and made nearly impenetrable by the massive limestone formation—the tsingy—running through it.