I don't think it was the ant unless you saw a piece of plant matter on its back. They don't eat leaves (they can't digest the material), but I don't see why they wouldn't use the plant material for other reasons (such as stabilizing their colony structure).
If your seeing any ants this time of year they are most likely Pharaoh Ants that are surviving in your home year round , Wild populations are still in hibernation with exceptions of course ..
maybe sprinkle glitter around the ants,
they'll think they're on the wrong planet.
[video=youtube;L5VVNnGCuYI]http://www.youtube.com/watch?v=L5VVNnGCuYI[/video]