Great Moments In Alternate History: The Land Before TimeS

The Earth existed for four billion or so years before humans showed up and started recording history. Why limit ourselves to the what-ifs of the past few thousands years? In these alternate reality tales, continents and dinosaur empires rise and fall.

65 million years ago, some disaster - probably caused by an asteroid - wiped out the dinosaurs. History then gave way to our mammal ancestors and, eventually, us. But what if the asteroid never showed up? Well, then you get intelligent dinosaur civilizations as in Harry Harrison's West of Eden. The Yilané, as Harrison names the dinosaur (okay, technically lizard) race, are masters of genetic engineering and have created everything from guns to submarines by modifying other species. The main conflict in West of Eden and its two sequels comes from the Yilané's discovery of a humanoid race, the Tanu, in North America.

Great Moments In Alternate History: The Land Before Time

A conflict between intelligent dinosaur and mammals species is also the subject of Taylor Anderson's Destroyermen series where a WWII battleship is sent to an alternate world where a race evolved from raptors is at war with a species of lemur-men. But sometimes dinosaur civilizations cause their own problems. In John E. Stith's One Giant Step an intelligent dinosaur race invents time travel and goes back sixty five million years where they accidentally cause their own extinction. This causes the rise of an intelligent insect society that invents time travel and...you get the idea.

Even when we manage to get rid of the dinosaurs we still have all the other hominids to worry about, or maybe they have to worry about us. In Harry Turtledove's A Different Flesh stories, Homo Erectus has survived in North America - when the humans arrive on the continent, the natives are viewed as sub-human monsters and enslaved. In Robert J. Sawyer's Neanderthal Parallax series a neanderthal physicist from an alternate universe ends up crossing over to our reality. This ends up going about as well for both civilizations as you might expect.

Great Moments In Alternate History: The Land Before Time

Neanderthals are also major characters in Harry Turtledove's Down in the Bottomlands but the added twist here is a huge geographic change to the surface of the earth. In the timeline of Bottomlands, the Mediterranean sea is a dry Mediterranean basin forming Europe and Africa into a single supercontinent and creating a timeline where Humans and Neanderthals survived to the present day. Turtledove explores a similar premise in his Atlantis series in which a huge chunk of North America broke off millions of years ago and created an 8th continent.

And as long as we're going way way back, we'd might as well go back a few billion years cover some what-ifs from the very beginning. Neil F. Comin's What if the Moon Didn't Exist: Voyages to Earths that Might Have Been is a series of essays that explores not just a moonless earth but earths with less mass or larger suns or a half dozen other strange formulations of our planet.