Idle Cavefish Offer Clues

They haven’t gone extinct yet.
They settled in and slowed down.
Their eyes decayed in the dark.

Their metabolisms slowed.
Longer life, a slower pace.
So what? The first in the cave

Arrived as they were. Offspring
That fared poorly fared poorly.
Offspring that fared well fared well.

Any generation sat
In the dark with what it had
And lived however it could.

It just happens now you have
These generations suited
To this life and nothing else.