On Monday morning I biked from Pilsen to Hyde Park. It was a pleasant ride. The return journey was taxing, though, since my legs were tired and—thanks to a late lunch—were competing with my stomach for oxygen. About halfway through the ride, on one of the Lake Shore Path’s many curves, I glanced over my shoulder: Not three feet behind me was another cyclist! Perhaps he’s about to pass me, I thought. But when I looked at the ground a minute later I saw a shadow in the grass, immediately behind my own. Another minute, another glance; I was beginning to feel unsettled. Just then the biker pulled ahead. But not far ahead. Did he mean for me to draft behind him? Was he returning the favor? I decided to see. As soon as I’d entered the pocket of air behind the stranger’s bike I felt the difference. I hardly needed to pedal. I breezed behind him for a mile and then we switched positions again. A little later on we switched once more. Each time I led I wasn’t sure if the stranger was still there. The only sign of his presence, when I cared to sneak a glance, was the shadow gliding beside me in the grass.
We biked like that for a few miles. The situation reminded me of biology class and of the symbiotic relationships that occasionally spring up between organisms of different species. As my turn off approached I turned to say goodbye to the stranger, to make this a human interaction, but there was no one there.