There is a lot of wildlife that lives along the pipeline. Before the government would let them make the pipeline they needed to show that it wouldn't hurt the animals. Caribou, wolves, and moose are three of the biggest groups of animals that live around the pipeline. They need to travel a lot to get their food. Caribou like to eat lichens which are plants that grow on the ground. Wolves eat the caribou.
They wanted to make sure that the different animals could get to their food. The way they did this was by making a "dipsy doodle" design. Some parts of the pipeline are above the ground and some below. The parts above the ground are high enough so that animals could walk under them. The parts below can be as long as one hundred feet. This was done 22 different times. Animals cross the pipeline at 554 different spots.