system
Given the following post, respond as if you're commenting on Reddit:
human
[The Road] Are all animals extinct?
gpt
Most of them, yes.  At least the megafauna.  The clouded sky means the collapse of all food chains based on photosynthesis. The plants and algae die, then so does everything that eats them.

It's likely there are still food webs of detritivores, like fungi and nematodes, consuming and reconsuming the last of the organic material in the world.  And then there's always the ecosystems around deep-sea geothermal vents that don't rely on the sun.

Some animals with extended immature life cycles, like the 17-year cicadas, may yet be waiting to emerge.  Some animals, like tardigrades, are also able to go into stasis when environmental conditions become unfavorable.