Nuclear traces in whales' teeth help scientists reconstruct their life stories

Scientists have used traces of radioactive fallout from nuclear weapons testing found in the teeth of stranded whales to reconstruct their life stories. Researchers from Scottish universities and museums conducted a radiocarbon dating analysis on samples from the teeth of sperm whales and killer whales that died on Scottish shores years ago.

Each growth layer in a whale's tooth is thought to form annually, like the rings of a tree. By testing this assumption, the researchers were able to gather clues about the whales' origins, diet, and lifespan. The findings, published in the journal Frontiers in Marine Science, provide new insights into the life cycles of these two whale species.

The study also sheds light on how whale teeth develop as they age. The research involved analyzing teeth from two sperm whales and three killer whales, including Moby, a sperm whale whose skull is displayed at the National Museum of Scotland, and Lulu, a killer whale from the West Coast Community pod. The study's lead author, Dr. Kieran Tierney, expressed personal pride in using Moby's tooth to help understand his life.

The analysis revealed that Moby was at least 43 years old when he died in 1997, while one of the killer whales studied was among the oldest known males of his type, potentially born in the early 1960s and possibly living to 65 or older. The tooth from Lulu showed a different radioactive fingerprint, indicating she was born before nuclear weapons testing affected radiocarbon levels.