Well, spiders don't grow like us, because they're arthropods. =D They have a exoskeleton, that's exchanged from time to time, thus allowing the spider to keep growing, this process is called Ecdysis (or "molt"), and yes, it's for all the arthropods. You may be asking, "so?". It's a awesome process, keep reading and you won't regret.
It all start when the exoskeleton starts to be tight, then the spider becomes inactive for a period of time (like a week or two), after this time it makes a thin "bed" of silk and lies upside down on it:
After lie, it start the process,the exoskeleton is opened by its prosoma ("head" or cephalothorax)and most of times the abdomen is ripped:
and for two hours long this happens:
After this, it becomes whitish and walks a little weird because the new exoskeleton is not hard as the old one, but it takes a short time to back to normal:
The old exoskeleton:
That's it, more photos:
*WATCH the videos!!!!