Tiziri.

The upper sector is the most spread out in Ghardaïa and the farthest from the depot, and Tiziri walks all of it. She stops in the middle of the road, crouches down, presses her open hand flat against the asphalt, and stays there for a long while, silent, before taking out the device. By the time she finally measures, the spot is already marked. And everything she needs for that — the gear, the reports, whatever comes up along the way — stays with her the whole night, slung over one shoulder. None of it gets left anywhere.

The sand cat weighs between 1.4 and 3.4 kilos and attacks venomous desert snakes: it's one of the few wild cat species documented hunting vipers with any regularity. Tiziri lives far from all that, in Ghardaïa, a city of pale stone in the M'zab valley. A dry wadi runs beneath it that people cross on foot like it's just another street. Some year or other it comes down full, and the whole city turns out to watch the flood get shared among the palm groves, through canals and sluice gates, arguing over the height of a stone if it comes to that.