Chris Kratt and Martin Kratt, commonly known as the Kratt Brothers, are the main protagonists of Wild Kratts. They are based on the famous Kratt Brothers of real life.
Martin Kratt (voiced by himself) - Martin (wearing blue) likes to give names to animals he finds, allowing the audience to bond with the animal. Martin is more the jokester of the two Kratt brothers. He is also often rushing and impulsive, unlike his younger brother, Chris. Martin is a little disorganized, emotional, and excited but knows when to be serious. In contrast to his brother Chris' climbing skills, Martin is a more experienced swimmer. He also likes to get into the mind of the animal at various times, saying such things as "Be the walrus!" He has a childish heart, due to his fun and humorous nature. He enjoys playing tricks on his brother.
Chris Kratt (voiced by himself) - Chris (wearing green) is the exact opposite of his brother and the more methodical brother of the two. Unlike Martin, he likes to take his time testing animals' DNA to understand the animals better and save them from the villains. Chris is organized, intellectual, and calm. He is an experienced climber, although in one episode, he falls from a tree and develops acrophobia that later subsides. After this episode, there is a running gag that he falls from a tree unharmed.
- They were foreshadowed in an episode of Nature Cat as bats and where know as, "The Wild Batts".