Fossorial Burrowing Species - How to judge their size

[dr89]

I have three Australian species of spiders, two tarantulas and a wishbone spider. A lot of advise relates to the relative size of the spider (like size of feeder crickets).
Issue is, all three of them are burrowing kinds and probably nocturnal too. I haven't had a good look in months.
What's a good way to judge their body lengths?

I can sometimes see the back of the tarantulas hanging near the top of the burrows, but it they are facing me abdomen first as though they're trying to moon me.
Is there a way to use circumstantial evidence to determine how large a spider is? (like the diameter of a burrow's opening?)

 

[BoyFromLA]

You just have to be more observant.

 

[quirinus]

surveillance camera
to record them when outside..
except for that?
Follow advice above..

 

[jbooth]

Yeah, it's hard lol. I feed them after a molt really well a couple times, then it's their job to come out far enough to see the abdomen if they want fed again lol. Doesn't always work but 9 times out of 10 if I don't see it come out at all, it's already fat and I'm worrying and overfeeding.

 

[jbooth]

Video feed, freeze frame at mid pounce lol..

 

[Ultum4Spiderz]

Take a picture of them beside a quarter or something or just estimate there size.

 

[BoyFromLA]

You just have to be more observant.

I really did mean it. Because all of my fossorial tarantulas stay out of their burrow more than often.

 

[dr89]

I really did mean it. Because all of my fossorial tarantulas stay out of their burrow more than often.

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Did your tarantulas become more active as they became bigger? I read somewhere that T's are afraid of wide open spaces, but as they become bigger in comparison to their enclosure size they start to feel more secure walking around outside their burrow.

 

[TechnoGeek]

Tbh I never understood the appeal of a T that you don't even see often enough to tell how big it's become.. the argument that it makes seeing them more special and exciting when they do come out makes even less sense to me

 

[SpookySpooder]

Tbh I never understood the appeal of a T that you don't even see often enough to tell how big it's become.. the argument that it makes seeing them more special and exciting when they do come out makes even less sense to me

They come out regularly, just often in the hours most people are asleep. My T's are most active between the hours of midnight-5 AM, and often I see them wandering their enclosures late at night.

When they do show themselves, they're often spectacular. See: Cyriopagopus lividus

Here is an example of when my pet hole makes an appearance and looks around. This was taken around 2 AM.



How often your T is out and about has a lot to do with a few things I think--I've noticed sling size and temperament play a large role.

Something I also noticed that is touched on often is proper enclosure set up, when your enclosure is set up properly, the T is quite comfortable in using the entire enclosure as a "burrow/hide" and will often sit in the open or just at the entrance of the burrow.

 

[Spinnenfritzi]

My fossoriels are also seen every night.

Something I also noticed that is touched on often is proper enclosure set up, when your enclosure is set up properly, the T is quite comfortable in using the entire enclosure as a "burrow/hide" and will often sit in the open or just at the entrance of the burrow.

I have come to the same conclusion

 

[Scoot]

Throw a quarter in