I came across this ball surrounded by baby spiders the other day, and when I had a closer look I realised that it was in fact a ball made entirely of spiders. I have never seen something like this before, has anyone else?
I guess that the mother laid a large number of eggs together and they all hatched at the same time.

I have! I don't know what species it would be, though.
Kingfisher
That picture is gross. Spiders creep me out. Why do they have to produce so many babies? Does anyone know how many on average a spider can produce?
However I am impressed when they come to learning things because they never have a parent to show them how to be a spider.
Baby spiders get eaten by a lot of other creatures, including other baby spiders! If there weren't so many of them, none would survive.
Kingfisher
Baby spiders get eaten by a lot of other creatures, including other baby spiders! If there weren't so many of them, none would survive.
Kingfisher
Very true. Like many animals, spiders like these ones rely on producing as much offspring as possible to counteract the fact that most will not survive.
I had no idea spiders ate each other. Would they still eat each other when they are adults too?
That's why black widows are called that! I believe that there's a number of arachnids which eat the male after mating.
Update on baby spider ball: yes, one reason they form that ball is because they do all hatch out at once, and another reason is that, if spotted by a predator, it's both visually confusing to the predator (which thinks it's larger prey than it can handle) and harder to pick off one in a crowd than picking off a singleton.
Kingfisher
A friend of mine was watching a pair of garden spiders. The male approached the female on her web then backed away, so my friend took the male on his finger, allowed it to dangle a little on a thread and went to put it on the web nearer the female. Unfortunately, a gust of wind slammed the male into the web much harder than was planned and the female immediately pounced on the male and killed him. Male garden spiders pluck the web with their front legs to let the female know that they're coming courting rather than prey trapped in the web.
To see a picture of this go here:
http://www.rkmas.co.uk/garden_spider_02.html