Signs of premolt (By Steven Stewart)

How Do I Know if My Tarantula Is in Premolt?

1. The tarantula stops eating
This is probably the most obvious and common sign. You've been feeding your specimen regularly for several weeks, and suddenly it stops eating. Most species will stop feeding during their premolt period (although there are exceptions) as they prepare their bodies for the arduous process.
That is not to say that a tarantula might not stop feeding for other reasons. The G. rosea is known to fast for long periods of time, even when not in premolt. A stressed tarantula may also refuse food. Therefore, consider some of the other signs as well.

2. The tarantula has a fat, shiny abdomen
Most tarantulas ready for premolt will sport nice, plump abdomens up to 1.5 times the size of their carapace (or even larger for an over-stuffed specimen). If your tarantula has a nice, bulbous booty, and she has stopped eating, chances are she's in premolt. As the flesh around the area stretches, the abdomen may also appear to be shiny.
The shininess is often more evident in slings than their older, much hairier counterparts.

3.The tarantula's abdomen and overall color darkens.
As the new exoskeleton forms under the old one, the spider will often darken up a bit. This is particularly evident on the abdomen where new hairs can be seen through the stretched skin here. Many of my slings will have a dark spot on their abdomens when in premolt, and it will continue to grow the closer they get to the actual molt. For species that do a lot of hair kicking and therefore have a bald spot, this darkening is especially evident.

4. The tarantula becomes slower and more lethargic.
Not all of the indicators are physical; an observant keeper should notice some behavioral changes as well. Besides not eating, most of my tarantulas that are in premolt become less active and often more secretive. Keep an eye on your tarantula, and along with the physical signs listed above, look for a change in behavior. Some of my most hyper species become noticeably sluggish when they are in premolt.

5. The tarantula has buried itself in its den.
Some things to consider if your T buries itself due to premolt.
They are not in danger.
They will not suffocate.
They have not been buried alive.
They do not need to be rescued.
The tarantula is just looking for some privacy and security during this vulnerable period. The tarantula will reopen its den once is has molted and hardened up. DO NOT freak out and try to dig the poor creature out; you only run the risk of distressing the animal and possibly interrupting its molt.

6. The tarantula has constructed a hammock-like web "mat" in its enclosure.
This web is referred to as a "molt mat", and it is where the tarantula will flip over on its back when it molts. You may catch your premolt T laying layer after layer of web in a small area, and some of the new world species will actually kick hairs on the web as a form of protection. If you see this behavior, it means that your tarantula is about to molt very soon, usually within a day. For arboreal species, they will sometime build elevated "hammocks" off the ground for their molt mats or seal themselves in their funnel webs. This behavior serves the same purpose.

One more thing to remember for those who have not witnessed a tarantula molt.
That's right, this is normal behavior; this is the position they get in to molt.
DO NOT touch a spider in this position.
DO NOT flip over a spider in this position.
DO NOT throw away, flush, or bury a spider in this position.
DO NOT blow on it.
DO NOT spray it with water.
DO leave it alone and let it complete the exhausting task of molting in peace. Molting is a natural occurrence for a tarantula, but it is also a period where they are quite vulnerable.
Any fiddling with the animal could prove deadly to the T.

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