Ever gone to kill a spider (or humanely cup it to bring outside or whatever hippies do), and it zips away at insanely fast speed? It seems. Mind you, that still gives us a six-foot animal that runs at 50mph, That's why spiders can get a little bigger than the biggest insects. permalink. The fastest spider in the world was once the Tegenaria gigantea or giant house spider (found here in Ireland as well as worldwide) It can run How fast could a spider run if it was the size of a. Why is body length the relevant factor, rather than, say, mass? I hope Spidey can top. Log In To BuzzFeed. Shorten the process and move on with your life with this free guide from Funadvice. Related Questions How fast to spiders run? These could be used to see around corners via cameras in the tips and to manipulate objects indirectly. The crack researchers at .