What is the major theme explored in the play "a west indian mulatto sailor

The theme of the play is how human beings can go to any extend for their will to live and survive.

Explanation:

'Thrist' is a play written by Eugene O'Neill, where there are three characters namely - a gentleman, a dancer, and a west Indian mulatto sailor. This is a story of these three characters who were stucked in the middle of a sea. With neither water nor food, they had no hopes left for their survival.

They were ready to go at any limit, and were ready to make any sacrifices in order to remain alive. As the title of the play suggest, the theme itself is human thirst for survival instinct.