system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do horses start side by side while runners are spread at equal distance before the race?

Is the difference just negligible for horses? Don't we want the race to be the same length for all the participants?
gpt
They will generally only spread runners out to compensate if they are restricted to a certain lane during the race. In races where there's no "lane" (like horse racing) everyone can move to the innermost lane basically immediately.