"WHEN I heard the sad news of Lonesome George's death, my first thought was for his fibroblasts. In 2006, I wrote a book on this singular giant tortoise, the last of his kind from the Galapagos island of Pinta. "There are, as yet, no cells from Lonesome George in a freezer," I wrote as I explored the technical and ethical hurdles to cloning this one-of-a-kind animal. I thought - naively, I now realise - that my observation might nudge someone to pop a sliver of his skin into liquid nitrogen. At the time of his death last month this had not happened."