"Possessive behavior" refers to when someone excessively wants to control or own something or someone, often showing jealousy and refusing to share or let go. Full definition
As a dog grows in a familiar environment, it starts to display possessive behaviors towards food, toys and other pets. (animalso.com)
Online Dating Tip # 4 If an individual seems to be extremely needy or needs to talk to you every minute, this may be a sign of possessive behavior and should be recognized early. (dating-place.org)
Aggressive and possessive behavior towards other humans by the dog can be dealt with by having a place for the dog to go to when the owner is interacting with others. (chifriends.org)