I went to a garden party on a dairy farm several decades ago. The setting was beautiful, on a grassy lawn with great food, beverages, the weather was fine and lots of people. The farmer had a couple of dogs, Blue Heelers, I think they were. I suppose forty people were on the grass. Eventually we all realized that we were standing all clumped together.
The farmer stated: "It's those damn dogs." The dogs circled around the people on the lawn, and gently but firmly nudged us together! The farmer stated that it has happened before. The dogs have the instinct to bring order to a group spread out, and the people unconsciously move in to keep away from the dogs that are gently herding them together. Hilarious and true.