I feel the most a creature should have as a lifespan is 100. Not even that. What if you don't have poison? What if you want to be peaceful, but a leotah is going to terrorize you for 200 days? Living 40-50 days sounds reasonable. Sorry if I am being rude, I just don't feel that is a reasonable lifespan.
I was thinking because some like roleplaying (Or am I the only one?) with their nichelings, they should be able to build brambles in exchange for nesting material, but this could be how you get the nesting material, and basically move the bramble.
And that's why my Gods and Goddesses don't ever have backstory's. Maybe if they had some disaster happen during their life. But most of my tribes are all quiet and don't have lots of story.