Walking sticks, also known as stick insects, come in various sizes from 1/2 to 21 inches long. They have over 3,000 kinds and only male walking sticks can fly. Females lay between 100 to 1,200 eggs which hatch into nymphs that then grow into adults, eating leaves while living in forests and grasslands where they can be preyed on by animals such as tarantulas, birds, snakes, and crocodiles.