A dung heap is a frenzy of shoving and shovelling. “Never did adventurers hurrying from the four corners of the earth display such eagerness,” the French entomologist Jean-Henri Fabre once wrote.

It's not easy being a dung beetle. Besides the obvious fact that they eat, well, dung, the act of just getting a meal is an involved process. In the most elaborate carry-out scenario, the dung ...

The dung heap is being dismantled by a scrum of hermit crabs. When I crouch for a closer look, they freeze, waiting for me to make the next move. Yesterday, the dung was fresh—wet, dense and ...