This is a shot in the dark, but some time ago, someone on HN posted a link to a science fiction short story about a few animal species that thrived and became i

This is a shot in the dark, but some time ago, someone on HN posted a link to a science fiction short story about a few animal species that thrived and became intelligent in a post-apocalyptic, post-human world. One species was raccoons, along with ravens, who built air balloons for transportation. Fascinating read. I've been trying to find it for months. If anyone knows the story, please let me know. That would be wonderful.