These two would eat all day long if you let them but basically they only feed once a day, the more they eat the larger they get. They call them cows because they will graze in the grass all day if you let them.
Do they interact with each other?
I've told this story here before, but I know you'll appreciate it.
For a little over 1 horrible year of my life, I lived half way between Okeechobee Fla, and YeeHaw Junction (I kid you not, Google it)
Anyway, at times there were so many land tortoises out, and they would get hit by cars. I passed this big one, about a foot and a half long, and stopped my car to get it out of the road. When I picked it up, it pissed all over me. I must have scared it to death.
At least it was out of harms way.