Why does de Vaca begin working and trading with the American Indians he encountered?

De Vaca had understood that to survive in the land he needed to assimilate.

Explanation:

Álvar Núñez Cabeza de Vaca was one of the first Spanish explores on the shores of Americas and one of the only our survivors from the Narváez expedition of 1527.

He was able to survive because he learnt to assimilate with the American natives.

He became a faith healer and earned the trust of the people of the lands and was able too hold out until he was able to get back to the Spanish in Mexico in 1536.