Mystery dungeon bosses

Question

What determines how much hp a boss has because every boss has loads like once I counted the amount of damage wigglytuff can take and it was around 1200.
I can kind of guess why they've done this (so its not easy) but is there a way of finding out how much hp they have maybe possibly a link saying how much they can have
Plus when you befriend a boss such as mew or girintina they have normal hp

Answer 1

The Boss has that much HP because it's a boss. You think beating Darkrai is going to be easy? Also, i changes when you recruit it because running around with a Dialga at 750 HP just is too easy.

The Boss HP is always the same, it isn't determined by anything.