What characteristic allows wombat incisors to effectively handle tough, abrasive vegetation like grasses?

The incisors are continuously growing, ensuring replacement material is always available as the surfaces wear down.

Wombats are obligate grazers whose diet frequently involves tough vegetation, including grasses, roots, and bark, which contain silica that causes substantial wear on dental structures. To counteract this constant abrasion, wombats have evolved continuously growing incisors, a feature conceptually similar to that found in rodents. This perpetual growth mechanism guarantees that as the front surfaces of the teeth—made of enamel and dentine—are worn away through chewing and grinding, new material is continually supplied from the root structure, maintaining functional cutting edges. Furthermore, the design includes a self-sharpening mechanism where the slightly more curved lower incisors shear against the upper incisors, creating an efficient edge for cropping vegetation, essential for survival in resource-limited grazing environments.