+Anima is a manga written and illustrated by Natsumi Mukai. +Anima is about a children, who have the powers of animals, and to transform into the one they were assigned. The main characters are Husky, Cooro, Senri and Nana. They all have different animal powers, and they all had different experiences that happened to them in order for them to become +Anima.
The world takes place on a fictional island continent, split between two nations: Astaria and Sailand. Both are mostly desert countries, but Astaria has a bit more variety of environments.
In conclusion, I think that you should read the +Anima manga series.