Who's afraid of whom?

Don't worry, no spiders (or people) were harmed in the taking of this photo. Dot the Chilean Rose Tarantula (Grammostola rosea) hadn't been eating much of late. It's apparently not unusual for captive spiders to go off their food, just like they could go for months in their natural desert environments without any prey. But it seems that there was another biological process at work here. Dot was moulting, shedding her skin. Many other animals including humans do this, except with humans its a bit more of a gradual process. Just like all arthropods (arachnids, insects, myriapods, crustaceans and the like) Dot has a tough exoskeleton. It's a good system really, instead of an internal skeleton like you and I have, arthropods keep their skeleton on the outside where it offers extra protection, like a suit of armour, as well as support.

Except what happens when you want to grow? Well, you need a new suit of armour, which means you need to get rid of the old one first. This rather extreme form of moulting has to happen in arthropods because of this exoskeleton and is called ecdysis. It's a rather stressful experience for any creature, as you might imagine. They can also lose limbs in the process and are very vulnerable while they wait for their new skeleton to harden up. Thankfully, Dot's moult seems to have been a complete success.

Dot also relies on her exoskeleton for feeding as well as defence. The sizable fangs you can see are certainly long and sharp enough to pierce human skin and deliver a painful bite, Dot (and all other spiders) doesn't want to do this, insofar as an invertebrate is capable of wanting anything, but that's another debate. Often when tarantulas and other spiders use their fangs in self-defence, they will "dry-bite" and not use any of their precious venom. Spiders cannot eat people, and so unless you threaten them they will basically ignore you. Spiders can only eat liquids, so use their fangs to inject a venom into their prey, digest its innards and suck out the tasty liquefied cricket, fly or whatever it may be. Their fangs are actually modified arms, and so are part of their exoskeleton meaning that they also become completely useless while she moults. That does mean that they will grow as she does. It also means that while she is still drying out, she won't be too hungry just yet, but I'm sure she will be soon.

And if you're still worrying about those fangs, then consider this: of the 40,000 species of spider currently recognised none are able to eat a mammal any larger than a small rodent, and only 7 species have ever been known to kill humans. Of those 7 the deadliest is thought to be the Brazilian Wandering Spider (Phoneutria spp.). Brazilain Wandering Spiders generally kill about 1% of people who are ever bitten. Who's afraid of whom?