Mara has thick black hair, which she usually wears in a plait down to her shoulders. She also has thick dark eyebrows to match, each marching straight across the space above her brown eyes, which tend to have a forthright, even borderline defiant expression toward the world around her. As someone who is, even before she speaks Spanish with her family in public, recognizably Latina and from the American South, she has cultivated that expression deliberately. She has pierced ears, with earrings more fun than valuable as a rule, and her clothes are distinctly upper middle class in branding and appearance, further contributing to the great lack of resemblance between her and her older half-sister Jessica Hayles.