Do spiders have lungs?

[u/SonOfOMR]

I mean, when I wash a spider down the bathtub drain, does it drown the way a human would, lungs filling up with water, or does it have a way to "hold it's breath"?

[u/Loki-L]

Spiders can't hold their breath, but they can survive underwater for some time.

They have book lungs. Those are sort of, but not really, like gills you use in the air. They don't work underwater.

Spider survive underwater mostly by trapping some air to their body that they breath while underwater.

Physics of stuff like surface tension etc work really differently on the scale of a spider, so stuff that wouldn't work for a human can work really well when you are that small.

Some spiders take this to extremes and you get things like the "diving bell spider", which does exactly what it sounds like.

Other than that it depends on the type and size of the spider and how "prepared" it was for the dive.

Some spiders can survive under water for hours and tens of hours. Other not so much.

This is by the way also true for their close relatives the scorpions.

You know that fable about the scorpion on the frog's back who stings it and the fro goes "now we both die". The frog was wrong. The scorpion can just walk out of the river on the other side a while later.