If the batter doesn't hit the ball just right, he's in trouble. An amazing series of reactions propels a shortstop or third baseman into the path of a hard-hit ball. In two steps or less, he may have already caught the ball and fired it to first base for an out, with a swiftness and assurance acquired only through years of practice. Inherited skill alone just won't do the job. The human ability to estimate trajectories of moving objects is difficult to explain.
Good fielders begin their movement just as the ball is hit, without wasting even half a step.
An outfielder instantly begins running toward the spot where he thinks the ball will fall. Sometimes, he will make a running catch without losing a stride, thrusting his glove into position at the last second. The end is the net result of the start . . . So the great catches in the outfield are made with the initial move. The ability to accurately predict where the ball will be involves the extrapolative capacities of the brain, but these skills are not completely unique to humans.