Venezuela’s Unique Tepui Frogs Face New Perils

The tabletop mountains “tepui” in Venezuela are sheltered, otherworldly ecosystems.

Standing up to 3,000 metres (10,000ft) high and cut off from the rest of the world by their steep cliffs, much of the flora and fauna on the sandstone plateaux has evolved in isolation and is found nowhere else on Earth.

The isolated and inhospitable ecosystems of the tepui have forced animals to evolve in strange ways to survive on the rocky plateaux and mossy walls.

The tiny pebble toad (Oreophrynella nigra) cannot hop but can tuck its head in and roll away from predators in a ball resembling one of the plateaus’ tiny black pebbles. The Oreophrynella macconnelli, found on the slopes of the Roraima Tepui, is small enough to drop safely from the tree canopy to the forest floors to evade predators.

Many of these species are found only on a single tepui, giving them some of the smallest geographic distributions for any vertebrates in the world. But their rare evolutionary conditions also make them highly vulnerable.