Biologist Egor Kirillin is on a special mission. Deep in the Siberian wilderness in the Russian Republic of Sakha, he waits on the Olenjok river until reindeer come thundering into the water. 

The river crosses the huge herd's migration route south, and provides Kirillin's one chance to tag them with radio transmitters. It's not a job for the faint of heart, but it is the only way to gather vital data on these animals' migration patterns — and try to uncover why their numbers are falling.  

Meanwhile, Kirillin's colleague at the Siberian Branch of the Russian Academy of Sciences, ethnologist Alexander Volkovitsky is researching the life and customs of the Nenets.  

Nomadic reindeer herders who move with their domesticated herds animals by season, the Nenets cover exhausting distances across the Russian Arctic. Even small climatic changes can have a dramatic effect on their environment, and Volkovitsky wants to understand what global warming will mean for the Nenets' traditional way of life.

A film by Boas Schwarz