The Elephant Sanctuary in Hohenwald, Tennessee, provides a place for sick and elderly female elephants to retire and roam free. "Every elephant that comes here searches out someone that she then spends most all of her time with," co-founder Carol Buckley says.

Tarra, a 35-year-old Asian elephant, surprised every elephant and human at the sanctuary with the choice of her new best friend—a rescued guard dog named Bella. "Tarra is the one who likes to be different," Carol says. "I think it was Tarra searching out Bella and Bella finding that she could get all of her emotional needs met through this elephant."

The unlikely pair is inseparable. "When it's time to eat, they both eat together. They drink together. They sleep together. They play together," Carol says.