experiment: open Tor Network Map, and in Root Terminal execute "tcpdump -i eth0". (replace with whatever your network interface is) Now watch the Connection list in Tor Network Map as it generates outbound traffic...
Isnt it strange that just passive packet observation generates activity in Tor network?
tcpdump's default is to automatically reverse DNS lookups for all IP address it encounters and print them together with th IP address. To prevent this, use the-noption too.