The piles of faeces made by rock hyraxes hold clues to our own past Natalia Kuzmina / Alamy 
Fossilised piles of faeces, called middens, have revealed that a desert valley in Yemen was once a tropical oasis, which may have lasted in the dry region because of human land management practices.
Today, Wadi Sana is a dry, rocky desert. We knew that between 11,000 and 5000 years ago, the Arabian peninsula and Sahara desert were wetter than they are now, and some lake-bed deposits suggested that grasslands and trees may have grown elsewhere in the interior …
source: newscientist.com