Good point. Unfortunately, the links in the Smithsonianmag's article are broken and they don't provide much other information to find the original papers that r

Good point. Unfortunately, the links in the Smithsonianmag's article are broken and they don't provide much other information to find the original papers that reported this, so I don't know how the authors worked. Would be interesting to see which sample they took. [Edit] I found the original papers (see above), but unfortunately the relevant one is closed-access...