How do we know that the albatross was not afraid of the humans ? Why did the sailors hail it in God`s name ?

The sailors were the only living things in this frightening, enclosed world where the ice made terrible groaning sounds that echoed all around. Finally, an Albatross emerged from the mist, and the sailors revered it as a sign of good luck, as though it were a "Christian soul" sent by God to save them.