In the hills of Brazil’s Atlantic Rainforest, Ecologist Marcio Pie was ready to forsake his research expedition. Dozens of flea toads surrounded him but he could only hear their characteristic chirps when he stopped for 15 minutes and remained completely still.
These frogs may be the smallest vertebrates in the world, at roughly the size of a grain of rice. They are colored dark brown, the same color of the leaf litter they live under in cloud forests at high altitudes. And while their mating calls pack a surprising volume for something that small, they will clam up whenever they sense nearby footsteps, which might sound like an earthquake-like rumble.
“Once I fell asleep waiting for it to start calling,” says Pie, an ecologist at Edge Hill University in the United Kingdom. “Then it starting calling in my dreams and I woke up.”
