It was an expressway. There were no lights other than cars. You're not wrong, had a human sprinted at 20mph across the expressway in the dark, I'd have hit them, too. That being said, you're not supposed to swerve and I had less than a second to react from when I saw it. It was getting hit and there was nothing I could've done.

I am neither blaming you nor critiquing your actions. In fact I agree that we should not swerve. I was just making an observation that driving slightly slower in low visibility might help by giving you more time to notice an obstruction and brake while provide also providing more time for the obstruction to react and clear the road. At least very least, people might slow down enough so that the crash is no longer fatal to the person or animal being crashed into