Why was Salva so scared in the land of Atuot?

Salva was frightened by the tales he'd heard. He was afraid of being eaten by a lion.

In the Dinka language, the Atuot were called “the people of the lion.” Their region was inhabited by large herds of antelope, wildebeest, gnus—and the lions that preyed on them. The Dinka told stories about the Atuot. When an Atuot person died, he came back to Earth as a lion, with a great hunger for the human flesh he once had. The lions in the Atuot region were said to be the fiercest in the world.
Nights became uneasy. Salva woke often to the sound of roars in the distance and sometimes to the death-squeal of an animal under a lion’s claws.