I think we are entering a gross critter phase. We went on a hike today and he brought home a slug. It joins the worm from last week. These are the questions he NEEDS answered:
How can you tell male from female in slugs and worms?
Why are some slugs different sizes and colors? (theories include young and old or different species)
What is the slugs favorite food?
How long do they live?
Where Is the mouth?
Where does their poop come out?
How do they breathe?
Do they lay eggs?
Where are they in the winter?
Why do they have slime?
Plus, a bunch of other questions I have forgotten.

As you can see, we have a lot to learn.