Tyler, like one of his parents (it's a secret which one!), is a member of the secret society of shapeshifting lizard people that's supposed to control the world (nowadays they mostly just get together to play euchre). Even though he's only reptilian on one side of his family, he can absolutely shapeshift like any other lizard person - and indeed he was raised as an ordinary human. But unlike other lizards who take full human form in public, he deliberately chooses to present as a human/lizard hybrid in all contexts, because he feels it's misleading to hide that about himself. He wants the people around him to be aware of his lizard privileges.