There are around 2,700 different species of earthworms around the world. Some are brown, some are pink, some red, and some species are blue and green. While most people would think of earthworms as animals that live in the garden, some choose to use them in cooking. Earthworms can be a nutritious addition to the human diet due to their high levels of protein, with some types of earthworms containing 60-70 percent protein. Their bodies contain very little fat and are easy to cook as there are no bones.