I read this one many years ago. An alien life-force traveling the galaxy and looking for intelligent life form to merge with, comes to a prehistoric earth around the time of the dinosaurs. The life-force looks around but can't seem to find any species that really suits it's needs. So what happens. It decides , to split itself in half. One will stay on earth and merge selects a unremarkable species of Lizard which it hopes it will evolve into a suitable forms. The other half of itself goes back into space to continue it's search, but it promise to return to the same place it split off and remerge with the part that of itself that stay behind if if it finds a suitable life form. The part that stayed on earth stuck with the lizards helped them survive and every once in a while would go back to the meeting pace but the other other lifeforce never returned and over millions o years the lizards became mammals but never approached sentience and still periodically they would go to that same place , But as the aeons progressed theThe alien life force inside the mammals slowly weaker and died away. The backed the wrong horse the creatures that they had help to survive evolved to become Lemmings
I cannot remember the title of story or who wrote it.
I cannot remember the title of story or who wrote it.
