World’s Largest Spiderweb

0:00 If the sun were to disappear tomorrow,

0:01 these cave spiders could go on living for thousands of years,

0:05 completely in the dark.

0:07 If you go right to the border of Greece and Albania,

0:10 you head down this dark cave,

0:11 and then you wade through chest-high water for about 50 m,

0:14 you find something really strange.

0:17 This thick, spongy substance that is everywhere.

0:20 It spans 100 sq m, and if you look closely,

0:23 you find that it's teeming with 100,000 spiders.

0:26 [music] This is the world's largest spider web.

0:30 But what's strange is that this cave is in complete darkness.

0:33 There is no sun, so no photosynthesis,

0:36 and no plants or any other traditional sources of food.

0:39 So, how can these spiders survive?

0:42 Well, things get even weirder when scientists looked at the kinds of spiders.

0:45 They found two species, one bigger one and one smaller one.

0:49 Usually, the bigger one eats the smaller one,

0:51 but here they were living in harmony.

0:53 So, what was going on?

0:55 Well, they found the answer to both of these questions

0:58 when they looked at the walls of the cave,

1:00 which was covered in this white slime.

1:02 When they put this slime under the microscope,

1:05 they realized there were sulfur-eating bacteria there,

1:07 which were feeding off the high sulfur concentrations in the rock.

1:11 And cave flies would then eat that slime.

1:13 And so, you got millions of cave flies,

1:15 which ended up creating this near-infinite buffet for the spiders.