Erin Pickett at UC Santa Cruz, Long Marine Lab--You are what you eat, and well, so are elephant seals. At least as far as whiskers go- whisker composition changes with diet. There are a few biologists in the Costa lab studying diet using stable isotopes of whiskers. Last Spring five satellite tagged females were given a dose of an amino acid called glycine. Glycine is found naturally in the proteins of animals. Glycine made in the lab is full of nitrogen 15, a heavier version of a seal's biosynthesized nitrogen.