#35 - CASA DE TARANTULA #1

With this entry I start a series on tarantula enclosures. Blog #16 - "S.A.D.S." showed some of my preferred methods of raising young tarantulas, but this series will focus more on adult housing for various types. It will be an ongoing series that will run concurrent with the Tales from the Field series I recently began.

Dave Marschang asked in a blog comment about moisture for burrowers. He wrote: "What do you do about the burrowers who burrow to the bottom? flood their burrows?" He didn't specify exactly which burrowers he was referring to. My answer would be different if it was a scrub desert or grassland obligate burrower like America's own Aphonopelma or South American Grammostola (which can be kept without a deep burrow), an African burrower like Monocentropus balfouri (requiring some ability to burrow, but commonly kept with perhaps 6-8" of substrate) or a Old World tropical burrower like Haplopelma (requiring a great depth of moist soil). Since moisture is most important for the latter I am going to assume he did, in fact, mean popular Asian burrowers of the family Ornithoctoninae (e.g., Haplopelma, Ornithoctonus) and Selenocosmiinae (e.g., Chilobrachys, Orphnaecus).

I don't work with these type of spiders any longer, but I used to breed quite a few of them. They are often referred to as "pet holes" because proper housing includes providing a great depth of moist dirt, which they will burrow to the bottom of. The "cobalt blue" (Haplopelma lividum) is one of the best known of these spiders, and I have often told customers to take a photo of their pretty black and blue spider and tape it to the enclosure because if properly housed the spider will never be visible. They are rarely seen except during the dark of night when they may be near the top of the burrow waiting to ambush prey. In America, Chris Allen is someone known for his love of these types of spiders. The keepers that I always associate with them are Volker von Wirth and Martin Huber, both of Germany. Volker is well known for his taxonomy work with these spiders in addition to captive husbandry and propagation. Martin was well-known also as a breeder with a preference for Asian burrowers, but today he has largely disappeared from arachnoculture and is instead working with frogs, especially Phyllomedusinae (i.e., neotropical leaf or monkey tree frogs such as Agalychnis and Phyllomedusa). The housing that was popularized by both Volker and Martin is what most of us used to great effect, and it utilized a unique method for adding water to these deep burrowing tarantulas that lived deep in the dirt. Many of the images contained herein are from Volker and Martin who shared them with me for my keynote lecture at the 2007 British Tarantula Society Lectures.

© von Wirth or Huber

This first image shows a very simple "cereal container" style housing for Haplopelma lividum. These containers are tall and narrow and you can pack dirt around a large tube or broomstick near one front corner to create the burrow for the spider so it will be easier for you to view. I have used very similar containers, but usually chose somewhat wider and taller Rubbermaid containers that had space for larger species like big Chilobrachys or Haplopelma schmidti.

However, what is important to notice in this image is the row of holes at the bottom of the front. The upper ring of holes is for ventilation, but the bottom holes are both for soaking and draining (I'll explain this below). European keepers have a penchant for making their own terrariums out of glass and the next images from Volker or Martin shows how theirs looked and how they were filled around a pole to create the burrow.

© von Wirth or Huber

Here you see the top view on the left and the front view on the right. Note the perforated aluminum used at the rear of the top for ventilation, the sliding glass top and the same perforated aluminum at the bottom of the front to provide for the soaking and draining that I will describe.

The next photos show this type of enclosure in preparation and use. In the second image the cardboard box is being used as a funnel to pour dirt into the narrow enclosure. This type of housing is outstanding for keeping any of the Asian burrowers and could also be used for some New World species with similar habits.

© Martin Huber

© Martin Huber

© Martin Huber

© von Wirth or Huber

What is interesting about this type of housing though is the method of watering the enclosures. This brings us to Dave's question. And a photo is worth a thousand words ...

Periodically the enclosures would be set into a large tub of water. You can see in the enclosure nearest the front that the spider is at the surface. What happens is the water enters the enclosure at the bottom of the front and rises to the water depth in the tub. The spiders will escape the sudden flood by rising up their burrows and will be safe. The soil is "re-soaked" and then when the enclosures are removed the water will drain back out the "grating" of perforated metal or the simple soldering iron melted holes in the case of our first image of a plastic "cereal container" version of the same enclosure concept. The water is allowed to fully drain before the enclosures are returned to the shelves and eventually the spider will descend back to the chamber at the bottom where it lives.

© von Wirth or Huber

This is a very innovative method that I used for years. But let's talk about adding moisture to the substrate of burrowers that don't require the same elevated humidity and deep burrows. I have talked before about "moisture strata" with regards to substrate. What I mean by that is that the depth of substrate is stratified into varying degrees of moisture, with the bottom wettest and the top driest. For example, if I have six inches of soil in an enclosure for something like M. balfouri I may want the bottom two inches to be moist, the middle two inches to be damp and the upper two inches to be mostly dry. This is easily accomplished if you pour water down one corner or along one side of the enclosure. I also like to use long oil funnels that you can press down to the enclosure's bottom so the water is fed directly to the lower levels. In smaller containers a turkey baster can accomplish the same thing, and in vials you can make do with a pipette. Or just take a pencil or wooden chopstick and push down into the substrate as deep as possible along one side. This will break the "surface tension" and allow the water to percolate to the bottom. The idea behind "moisture strata" is to make the surface that is in contact with a terrestrial spider or a burrower that is in a shallow scrape relatively dry, but have a fair amount of water content below that evaporates and creates natural humidity.

The following two images show how I house my Harpactira. This plastic storage container has two large vents at each end (2" diameter hole saw cut holes covered on the outside with aluminum insect screening affixed by hot glue). This particular enclosure holds a subadult female H. marksi. I don't provide a great depth of substrate and the enclosure is both well-ventilated and kept fairly dry. What I do is provide a 2 oz. condiment cup of water, which really isn't for drinking except in an emergency*, but rather it is a small pool that I can overflow soaking the substrate in only one area of the enclosure. If the coco substrate becomes overly dry I will also pour water down along the length of the side as well. Note in the first photo how the coco is clearly darker right around the water cup (sprig of plastic plant is to prevent drowned crickets - never use cotton or paper towel or anything else that will foul and "breed" bacteria). The color of the coconut coir is a guide to how moist it is. You will also see that it has been moistened along the left side - the same side that the water cup is on. However, about 75% of the area is mostly dry including the area where you can see the silken entrance to the spider's shallow burrow.

© Michael Jacobi

© Michael Jacobi

I use a larger version of this "tub" with the same vent layout for my M. balfouri, and for that species I provide perhaps six to eight inches of substrate instead of the three to four you see here. However, my method of watering is the same: overflow the water dish for at least several seconds so that one corner of the enclosure is moist and, if necessary, also pour a bit down the length of one side. But I am always careful to not add too much water for "scrubland" species like Harpactira and Monocentropus.

* I have a saying that a tarantula never needs a water dish until it needs a water dish. Think about that ... none of my arboreals have them. They get moisture from their food and their enclosures are misted once or twice a week to elevate the humidity. If they really need to drink they will come out and use the droplets on the plants or the side of the glass or plastic at that time. Many are in natural terrariums with live plants and I water the plants and humidity is maintained by plant respiration and water evaporation. However, I do like to put a small dish (usually two 2 oz. condiments nested together; the bottom is the placeholder and the top is the disposable water container) in the enclosures of my African terrestrials (and recommend for other dry climate spiders). As discussed, I primarily use it as a point to pour water to re-moisten the substrate. They may never drink from them. But that one time that they have become too dry, or too underfed or too warm or too whatever they may seek a drink, and then it being there is the difference between life and death. Hence, I refer to them as " for emergency use". They don't need them ... until they do.

I hope you've learned something from Casa de Tarantula #1. In the second installment of this new series I will show you how to make a simple and perfect breeding enclosure for Poecilotheria using a large cereal container.

All the best, MJ