KAUTOKEINO, Norway — Reindeer herding is not a job for many Sami, an indigenous people of fewer than 140,000 who inhabit mostly the northern reaches of Sweden, Norway, Finland and Russia. It is a way of life.

Jovsset Ante Sara, a boyish-looking 26-year-old, knows his section of the tundra as if it were a city grid, every hill and valley familiar, the land acquired over generations through the meticulous work of his ancestors.

He can tell his reindeer from any others by their unique earmark. And he and his family need them to live and preserve their claim to the land as well as their traditions.

That’s why, Mr. Sara says, he has refused to abide by Norwegian laws, passed more than a decade ago, that limit the size of reindeer herds. The measure was taken, the government says, to prevent overgrazing.