Isso pode ser The Transall Saga de Gary Paulsen . O javali é mencionado em esta revisão :
In the beginning of the story, Mark is on a camping trip in the desert. He is with his parents, who are adventurers and he is having a great time. He is roaming along through the desert at night by when he spots a strange blue light shining from the skies. He climbs a rock to get a better view of this light, when the rock slides and he falls off into the light. When he wakes up he is stunned to find that he is no longer in the desert.
....
When food becomes a problem for Mark he goes out on a search and kills a big boar creature. This boar creature was attacking human looking animal so Mark killed it. Mark realizes that there are other human like creatures on the planet and he follows the girl to her tribe.
A maioria das capas são de cor laranja / amarelo: 