Millions of crabs become rivers of red as they move from Christmas Island's interior rainforests to the ocean to breed and lay eggs. During migration, red crabs climb over and around obstacles in their way, following the same migration paths every year.
Christmas Island red crabs live on Christmas Island in the Indian Ocean off Australia’s northern coast, about 240 miles (380 kilometers) south of Java, Indonesia. Red crabs must keep their bodies moist, so they wait for the rainy season to provide conditions that are ideal for the difficult journey. A single female can lay up to 100,000 eggs.