Three young scientists set traps to capture and film species of special concern in move that can help conserve the shrew

In a 7,000ft-high marshy spot in the cold, rugged eastern Sierra mountains, two groups of mammals scurried around at night. One was going about their normal nocturnal routine of hunting worms. The other was hoping for a glimpse of an elusive creature: the Mount Lyell shrew, the only known California mammal never photographed alive.

The three young student scientists faced a tight timeline. They baited 150 pitfall traps – small cups dug into the earth to catch wandering creatures – with cat food and mealworms and monitored them across a 600ft area, checking each trap every two hours for any signs of their goal. They slept no more than two hours at a time. Shrews have such a fast metabolism that they die in traps quickly, one of the reasons this species had never been photographed or studied live.