Paleontologists studying fossilised hominin teeth from the East African Rift have identified a series of deep, parallel grooves that have puzzled researchers for decades. The latest paper, published in *Nature Ecology & Evolution*, proposes three leading hypotheses: (1) a dietary habit involving abrasive plant materials, (2) a cultural practice of tooth‑filing for aesthetic or tribal reasons, and (3) post‑mortem mineral erosion in the burial environment. Microscopic analysis and experimental replication suggest that a combination of diet and cultural modification is the most plausible explanation, though further DNA and isotopic work is needed to confirm the theory.
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