Desert Rattleback

The desert rattleback is a large, not-so heavily armored species of rattleback from the North American Desert in 5 million AD, in The Future is Wild.

The Isthmus of Panama has not always been a true land bridge. For many millions of years before its formation, the two continents of the Americas were quite separate and distinct. When the connection first came to be, around 3 million BC in the Late Neogene (Pliocene epoch), terrestrial and freshwater animals migrated from north to south, while other terrestrial and freshwater animals spread into the opposite direction into North America. After this event (the Great American Interchange), one of the few South American mammals to have flourished in North America was the opossum.

Now, in 5 million AD, another South American mammal has made the journey - the rattleback. The rattleback evolved from the paca (Cuniculus), a large ground-dwelling rodent (comprising of three species) found in a wide variety of habitats in South America and a small portion of North America. South American rattlebacks were highly successful on the dry grasslands that were spreading across the Amazon Basin. So much so, in fact, that they were able to migrate northwards into the North American Desert. There, the rattleback evolved into yet another species, one adapted for the cold desert environment.