Duo is the official mascot of Duolingo. He is a green owl, similar to the spectacled owl species in the real world and is meant to symbolize knowledge, wisdom, and learning.[1] When you're using Duolingo, he can at times serve as a coach to motivate users to achieve higher learning goals, and can also instruct users on several aspects of the Duolingo website. As you're doing lessons, he will sometimes pop up to do things like giving encouragement.