The Musculoskeletal System of the Eastern Mole
The eastern mole, Scalopus aquaticus, is a small mammal known for living underground and rarely seen on the surface. Its muscular and skeletal features reveal many evolutionary adaptations for digging and surviving in subterranean tunnel systems, in addition to reflecting the animal’s dietary habits.
Starting with its elongated skull, the eastern mole has a weak zygomatic arch, the bone feature that supports the chewing muscle masseter. This means that the mole has very limited chewing ability. It corresponds to the fact that most of the mole’s diet contains “soft” food sources including earthworms, centipedes, spiders, ants, and slugs. The mole’s dietary habits also explain why it lacks strong…show more content… This is because the mole’s eyes are a vestigial structure. In other words, the eyes have lost most of their ancestral sensory function, and are merely the reminiscence of evolution. The eastern mole no longer needs its eyes to see a clear image because there is little light underground: they can only distinguish between dark and light. Instead, it uses its star-shaped nose and long tail for sensory information when navigating underground.
Additionally, in their book Mammalian Species, researchers Terry Yates and David Schmidly noted that two other identifying features of the mole are its inflated bone around the inner ear and hard palate that extends beyond the molars.
Moving pass the skull, one of the most notable features of the mole’s dorsal are its enormous front feet. These front feet are evolved so that the mole can dig underground with ease. In fact, the first part of the eastern mole’s scientific name, Scalopus, is derived from the two Greeks words meaning “digging” and “foot” (skalops: to dig; pous: foot). The enlarged front feet are broader than they are long, creating a large surface to remove dirt, similar to the large and flat surface of a shovel. The front feet also naturally point outward due to the way the radius articulates with the humerus. This unique position of the front feet produces strong lateral digging forces, a crucial force for removal large amount of dirt underground.…show more content… This is because the mole needs to move freely in narrow tunnels. The hind feet are miniature, and contain a fringe of sensory hairs that helps in excavating operations. The pelvic girdle is also very narrow, permitting the mole to turn around in its tunnel by doing a partial somersault or doubling back upon itself. The pelvis also has the potential for elastic energy storage. As the mole tunnels underground, it also needs to absorb impact and able to move freely toward its rare, so its pelvis skeleton consists more elastic
