Alexandra Kralick is a Ph.D. student in anthropology at the University of Pennsylvania. She studies the growth and development of sex differences in the great ape and human skeleton in the subdiscipline of biological anthropology. Her previous work is on gorilla dental development and wrist bone shape. Kralick is a National Science Foundation Graduate Research Fellow. She earned her B.S. in biological anthropology from George Washington University. Follow her on Twitter @BioAnthFunFacts.