Special Sauce

The idea of animals gaining sentience has been done before, so has the idea of split earths with segments of the population being separated, but here these two elements are combined. The idea that a geostorm split the earth, and put all the animals on a new duplicate earth and left all the people, without animals, on the original earth is a new twist. Throw in a portal to be discovered between the two earths, and it is a very fresh idea indeed.