In the August issue of Scientific American, physiologist Kevin Campbell of the University of Manitoba in Canada and molecular biologist Michael Hofreiter of the University of York in England describe recent advances in biotechnology that are enabling researchers to reassemble genes from long-vanished creatures and resurrect the proteins those genes encode. Their efforts have demonstrated that it is possible to observe physiological processes that took place in animals that have been extinct for thousands of years. The interactive below shows how Campbell and Hofreiter recreated the red blood cell protein hemoglobin from a woolly mammoth and then observed how that protein functioned, revealing a key adaptation to cold climate.