Ancient rhino teeth unlock 20-million-year-old secrets in Canada

By Mary McAuliffe July 16, 2025
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Modern Rhinos (Wikimedia Commons/Public Domain: Komencanto)

Scientists have sequenced tooth enamel proteins from an Early Miocene rhinocerotid that lived tens of millions of years ago in what is now Canada’s High Arctic, according to groundbreaking study published in Nature.

Living roughly 21 million to 24 million years ago, the rhino is the oldest mammalian proteome ever recovered. Unlike DNA, these sturdy enamel proteins survive deep time in the deep cold, allowing researchers to rewrite parts of the rhino family tree and confirm that Arctic fossil sites can preserve molecular evidence far beyond what was thought possible before.

“It really does change the way we have to think about the evolution of rhinos,” said study co-leader Ryan Paterson, a biomolecular palaeontologist at the University of Copenhagen. He told Nature that the fossil came from a polar desert, where consistently freezing temperatures created the “perfect place” for protein preservation, opening a world of possibilities for studying deep-time evolution.

 

Location of Devon Island in the circumpolar North (map data from International Bathymetric Chart of the Arctic Ocean, accessed via ArcGIS on 8 May 2024). b, Anterolingual view of specimen CMNFV59632 after destructive palaeoproteomic analysis. c, Location of Haughton Crater on Devon Island. Scale bar, 1 cm (b). Panel a adapted from ref. 48, Springer Nature Ltd.

Key Takeaways: 

  • Proteins survive far past DNA’s limit
    Enamel proteins from the Arctic rhino tooth—dated to 21–24 million years ago—are the oldest mammalian proteins ever sequenced, shattering the ~1-million-year ceiling set by ancient DNA.
  • Unlocking new evolutionary timelines
    The team retrieved seven enamel proteins with over 1,000 peptide-spectrum matches, enabling Bayesian tip-dating that repositioned the rhino’s lineage split to between the Middle Eocene and Oligocene, which is far older than previously believed.
  • Arctic preservation proved incredibly effective
    Cold, stable conditions in the High Arctic combined with enamel’s shielding properties created the perfect environment for long-term protein preservation.
  • Proteomics opens new doors
    Researchers say this study raises a whole new range of questions that paleontologists never imagined they could explore, including the exciting potential to gain proteomic insights into ancient mammals, possibly even dinosaurs.

By demonstrating that enamel proteomics can reach deep into geological time, researchers can now rewrite evolutionary histories, paving the way for molecular studies of fossils once thought too old to reveal their secrets. You can read the full study here.

Mary McAuliffe, formerly a Jerusalem-based correspondent for an international news channel, is a freelance journalist, photographer and filmmaker, covering the most pressing issues facing society for television, digital, and radio.