For some reason I'm having trouble thinking up which NW are obligate burrowers. I know that the majority of NW slings are burrowers, and as they grow they take advantage of hides.
Megaphobema robustum is a NW Obliagte burrower I believe.
Most Aphonopelma spp. are obligate burrowers in the wild, but take advantage of hides and such in captivity. Note: Obligate burrowing for Aphonpelma and Hapopelma is not the same, atleast I choose to think so.
There are plenty more, that I'm sure people will come to discuss soon.
That's what the other word I was trying to think of is.. opportunistic versus obligate burrowers.
this was a question that had just come to mind when I heard someone mention that adult aphonopelma's could be found in a burrow has shallow as 4 inches down. Not sure if those were under more sheltered areas like under rocks so that there was no need to dig deeper or what.
I have an A. anax spiderling that I've had since 2005. It did not make a burrow until recently when it finally decided to go into pre-molt. Then it dug like crazy and stayed put till it molted.
I remember my male T blondi when he was alive liked to dig a lot, excavating from within a provided hide.
My B. emilia's seem to like moving dirt around but not make a burrow or hide in the process they just moving dirt around lol.
I have a B. smithi that burrowed under a shallow plastic deli cup when she was young, but stopped using that hole as a hide when she got bigger...she still likes to sit in the deli cup from time to time though so I have not had the heart to remove it. I've had other B. smithi's that never dug at all. My B. auratum does not dig at all...just hangs out on the side of the jar waiting for a cricket to get dropped in lol.
The G. pulchras I have always seem to go 50/50... some would burrow while others didn't.
I hear C. fasciatus are supposed to be burrowers to some extent, but I have one that has never done it.