The Goliath Spider also know as the Goliath Bird Eating Spider is quite possibly the largest species of tarantula in the world. They have a 12 inch leg span and are about the size of a dinner plate or a small pizza, and can weigh up to about 2.5 ounces. Just like many other species of spiders they lack antennae's and have four pairs of legs. They have two external body parts, one being the cephalothorax or the head and neck combined, and the other being the abdomen. Although they have eight eyes, they have very weak eyesight and can only see the difference in levels of light. They mainly rely on sensory hairs to detect vibrations in the ground and in the air. Nerve cells at the end of each hair allow them to detect for movement.