This section temporarily contains information copied directly from Bulbapedia, and needs to be rewritten so not to be classified as plagiarism.
“Sandshrew have historically lived in desert areas. But the frequent eruptions of nearby volcanoes drove the Sandshrew to abandon the desert and migrate to snowy mountains, where they took on this form. Sandshrew’s body changed to adapt to the harsh environment of the snowy mountains. The Alolan Sandshrew has a shell of ice covering its skin, which is like hard steel. It excels defensively, but it lacks flexibility and can’t curl its body into a ball like a Ground-type Sandshrew can. Its heavy weight makes the Alolan Sandshrew slower than a normal Sandshrew, but the claws on its hands and feet allow it to move across ice without slipping. When it wants to move quickly, it uses its stomach to slide across the ice like a curling rock.”
In Alola, Sandshrew migrated to the snowy mountains due to the frequent activity of the volcanoes near the desert areas. In the process of this adaptation, Sandshrew's body became larger and heavier, and its hide became white and snowlike, with a shell of hard ice covering it for extra protection. Its head now resembles an igloo, with the dome forming a protective helmet around its head and its ears resembling an igloo's entrance. Alolan Sandshrew's claws allow it to move without slipping on icy surfaces. It slides on its stomach when it needs to move quickly.