Bears like the internet towers because they are ideal for scratching that part of their backs that they can't normally itch.
Your average bear will rub against a tower and cause it to lose line of site connections. Barry Ramsay told the Times that when it happened work crews had to ride up in snowmobiles to discover the problem.
quelle: http://news.techeye.net/internet/intern ... d-by-bears
http://www.nytimes.com/2011/09/14/us/do ... ted=1&_r=2