Spiders

Do spiders hibernate?  Apparently they must do, because after a winter of inactivity I've been seeing loads over the last few days.  It really is quite unsettling.  Like they've been biding their time over winter until a certain temperature is reached again and they are reactivated.  All of them.  At once.  And not uncoincidentally we have had some nice weather this week.  Disturbing.