A biologist is a scientist who studies living things. Biologists investigate everything from tiny bacteria you can only see through a microscope to enormous whales swimming in the ocean. They explore questions like: How do plants make food from sunlight? Why do some animals hibernate? What makes our hearts beat? How do birds know where to migrate?

Different biologists specialize in different areas. A marine biologist studies ocean life, while a microbiologist examines organisms too small to see without a microscope. Wildlife biologists track animals in their natural habitats, and molecular biologists study the chemical processes inside cells.

Biologists work in many places: laboratories, forests, oceans, universities, hospitals, and zoos. Some discover new species in the rainforest. Others develop medicines or work to protect endangered animals. Jane Goodall, who spent decades observing chimpanzees in Africa, is a famous biologist whose patient work taught us how intelligent and social chimpanzees are.