Originally posted by Pevy:

You might not be aware, but when you kill a boss, that triggers that bosses biomes mobs, to spawn in all lower biomes if i recall correct. Other wise it might just be Meadows who have everything spawning.

But i can tell you that if you look around, its not only fulings who spawn, also skeletons do and other stuff.

Skellies rampage all night in the meadows after defeating Bonemass. It's fun watching the skelly/greydwarf/deer/neck war from the comfort of my porch.