Why The Ear

I don't know much about training a catch dog but I do know not to grab a bull by the horns. I do not want my dog in front of the hog. I know stuff happens. But in my dream world the dogs are baying and the catch dog dog comes up and grabs the ear and stays right beside the hog. Not in front but beside the hog. There aint no cutters on the side of the body. But this aint Mr. Rogers Neighborhood so do what works for you. The question was, Why the ear? Not why the ear and not anywhere else? The ear seems like a great handle to hold on to for some dogs. Is it the best? I say don't grab a bull by the horns. Let him run by and grab him him by the cahonies. I bet that would stop the hog fast. But there are sows and barrs so I guess it will be the ear will have to do.