07/19/2010 at 01:00 AM EDT
Jane Goodall first set foot in Tanzania 50 years ago this month. She was 26 and required by British officials to bring her mom for safety. But the self-taught English primatologist's observations of chimpanzees proved revolutionary-she was the first to note that chimps use tools (blades of grass to capture termites) and communicate like humans. Today, at 76, Goodall travels the globe at least 300 days a year to advocate for her beloved animals. "Though chimps' numbers have plummeted," she says, "I still have hope." For more information, visit the Jane Goodall Institute at janegoodall.org.