My insurance currently does not cover my snakes, but it does cover my cages/thermostats/things like that up to $20,000 but that covers everything in my apartment (I have $10,000 in computer equipment alone so you do the math on that one)
All I have to do is have everything documented (purchase price/date, photos of items)
I have multiple digital copies of this documentation (on my computer, on my parents computer, and on the cloud)
I also have a hard copy in my firesafe