territoriality

from WordNet (r) 3.0 (2006)

territoriality
    n 1: the behavior of a male animal that defines and defends its
         territory

from The Collaborative International Dictionary of English v.0.48

Territoriality \Ter`ri*to`ri*al"i*ty\ n. (Zool.)
   a pattern of behavior characterized by the marking and
   defense of a home territory, exhibited by certain male
   animals.
   [WordNet 1.5 +PJC]