In this week's Lucretius Today podcast (Episode 274), Cicero relates this about Democritus (the underlined section):
I will have nothing at all to do with that fortuitous concourse of individual light and round bodies, notwithstanding Democritus insists on their being warm, and having breath, that is to say, life. But this soul, which is compounded of either of the four principles from which we assert that all things are derived, is of inflamed air, as seems particularly to have been the opinion of Panætius, and must necessarily mount upwards; for air and fire have no tendency downwards, but always ascend; so should they be dissipated, that must be at some distance from the earth; but should they remain, and preserve their original state, it is clearer still that they must be carried heavenward; and this gross and concrete air, which is nearest the earth, must be divided and broken by them; for the soul is warmer, or rather hotter than that air, which I just now called gross and concrete; and this may be made evident from this consideration,—that our bodies, being compounded of the earthy class of principles, grow warm by the heat of the soul.
Thus the question in the title - Democritus did not apparently come up with the swerve, but did he think that atoms can be alive?
I checked and I don't think we have made any effort to make up a chart of differences between Epicurus and Democritus, and we need to develop one. If anyone already has one or knows of links please post, and let's develop one. There seem to be many and deep differences and we need to have this information readily available. Democritus was certainly a great man, but did he fully break from supernatural religion? That, at the very least, needs to be something we are very clear about.