Summary: Monarch butterflies make an incredible, multi-generational migration from Canada to Mexico, but, strangely, they do not take the the most direct route. Somewhere over Lake Superior, these butterflies always change direction drastically, as if avoiding something. New research suggests that there was once a mountain range in the exact position of the course correction, and every generation of monarch butterfly somehow remembers to circumvent it, even thousands of yours later. Jeff and Anthony are mystified by this phenomena, but that doesn't stop them from speculating on how and why this unnecessary extra effort takes place.
