the external part of the ear. These features reduce drag when it digs and when it moves through tunnels. Digging and burrowing The shrew-mole is often confused with pocket gophers, another group of fossorial subterranean mammals, because they have similar habits but they differ greatly in the methods for burrowing. Most fossorial mammals, including the pocket gophers dig with their forepaws held directly below their body, but shrew-moles dig using lateral-strokes. This method of lateral-stroke burrowing in shrew moles is an evolutionary adaptation due to the modification of the pectoral girdle and bones of the forelimbs. The pelvic girdle is small and unmodified, but the pectoral girdle contains a special joint that causes the clavicle to join with the humerus instead of the scapula. The humerus bones are unique to shrew-moles because they exist as massive rectangular shapes, unlike other fossorial mammalian groups. The humerus also has a large surface area for the attachment of well developed muscles used for digging. The shrew-mole makes permanent tunnels by digging with its forelimbs and using its forefeet to soften the soil that will be removed to make a hollow tunnel. The tunnels form complex networks that interconnect and lead to burrows. The tunnels are rarely ever deeper than 30 centimeters below the surface, so they are not as deep as the tunnels of other mole species. The burrows are made beneath decaying leaf litter and have an opening on the ceiling that leads to the surface, which serves the purpose of ventilation. The shrew-mole also makes shallow surface runways by moving the front part of its body 45 degrees to the right and then to the left. Then back again to the right, then left, and so on. When it moves to the right, the left forepaw is thrust up rapidly lifting soil in the process and when it moves to the left, the right forepaw is thrust up to lift soil. As the shrew-mole continues to dig through the soil, the amount of prey in the soil is significantly less than the amount present in soil that has not been dug through by them. In addition, it spends a lot of its energy to dig through the soil. Due to these factors, it is common for shrew-moles to forage through tunnels that have been dug by other shrew-moles because it is more energetically efficient and more prey might be present in