This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: New analysis of traces of radioactive fallout from nuclear weapons testing trapped in the teeth of stranded whales has helped scientists reconstruct their life stories. A team of researchers from Scottish universities and museums used sophisticated radiocarbon dating techniques on samples of whale teeth to create a kind of dental time machine.
Each growth layer in a whale's tooth is thought to form annually, like the rings of a tree. The researchers tested that assumption for the first time in sperm whales and killer whales by using bomb radiocarbon. These harmless trace radiocarbon signals, together with stable isotopes, provided clues about where the whales called home, what they ate and how long they lived.
Conclusions drawn from those clues have enabled the researchers to roll back the years to uncover details about the whales' lives. Their findings, published as a paper in the journal Frontiers in Marine Science, are based on the analysis of teeth collected from two sperm whales and three killer whales that died on Scottish shores in decades past. The outcomes of the study could help broaden scientists' understanding of the life cycles of the two whale species, with one killer whale studied being among the oldest known males of his type ever documented.
The paper also provides new insight into how whales' teeth develop as they age. The researchers' analysis represents some of the first direct evidence that tooth growth layers are created annually during early to midlife and suggests that they become less reliable as an age marker as the marine mammals enter their senior years. The teeth analyzed included samples from two high-profile Scottish whale strandings.
Sperm whale Moby, whose skull is today on display in the National Museum of Scotland, became stranded on mudflats along the Firth of Forth in 1997. Lulu, a member of the West Coast Community pod of killer whales, washed ashore on Tiree in 2016 with signs of entanglement. The research was led by scientists at SUERC: Centre for the Isotope Sciences in partnership with researchers from the universities of Glasgow, Edinburgh and St Andrews and National Museums Scotland.
For the paper's lead author, Dr. Kieran Tierney, of SUERC: Centre for the Isotope Sciences, the research has a personal resonance. He said, "My parents took me to see Moby when he arrived in the Firth of Forth in 1997, when I was 6 years old.
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