Life of cows and bulls

A bunch of cows and bulls are standing in a field. A huge gust of wind comes along and all the cows fall over, but the bulls just stand there, bracing themselves against the gale. So all the cows stand up and brush themselves off and go back to their business. Pretty soon, a tornado blows through and all of the cows are knocked to the ground, but the bulls just munch on the grass. Next, a hurricane comes through and all the cows are knocked into the next pasture. The bulls just say "moo." Finally, one of the cows walks up to one of the bulls and says, "Moo? What's the mooing deal? How come the wind always knocks us for a loop and you just stand there unharmed ?" "Isn't it obvious?" the bull replies. "We bulls wobble, but we don't fall down."