Researchers say terrier and shepherd breeds display greater tendency for addictive-type behaviour Researchers say terrier and shepherd breeds display greater tendency for addictive-type behaviour Whether it is a spaniel with an insatiable love for a ball or a flat-coat that cannot be without its squeaky bear, dogs can be very keen on their toys. Now researchers say some may even show signs of addiction. While humans can take a host of activities to excess, from work to shopping, only gambling