I think it was the Great Race Able and Cain had...They wanted to see who was the fastest one to be able to catch sheep, so they Raced across the field, But one of them ( I forget ) fell and hit his head on a rock and died...but I think that was the first race ever...Hope this Helps...:)
There were no 'races' as such in the beginning. There were just humans trying to populate the earth after bring kicked out of Eden. Races as we understand them began when God scattered the people as punishment for being so arrogant as to try and reach heaven via a human works. At this time separation of languages began. Skin colors may have taken more time as people gathered in language groups and spread over the earth and began adapting to local environments.