There’s the oddest photo in a new book from the Denver Museum of Nature & Science. A man in a lab coat is performing a CAT scan. The subject of the scan isn’t human. It isn’t even alive. It’s the skull of a giant Ice Age bison. This is just one of countless tests that followed a huge discovery of prehistoric animals bones and plants near Snowmass in late 2010. A new book "Digging Snowmastodon" retraces the drama of the excavation, the cataloguing, and what it’s all taught scientists so far. Ryan Warner speaks with Kirk Johnson who is one of the authors.

[Photo: CPR News]