Chaninho the cat is happy and he knows it, so he meows!
Bobby told Love Meow: "This guy discovered a hidden talent that his cat Chaninho possessed where he can sing along to children's songs like this Portuguese version of 'If You're Happy and You Know It'. However, since the cat can't 'clap' to show that he's happy and he knows it, he just has to meow instead."
Chaninho is not the only cat that loves to sing duets with his human. Remember Max the Maine Coon who sings Twinkle Twinkle Little Star?