What Ray Bradbury short story is this?

A man is on a planet and runs into animals lined up and frozen (unanimated) for a collection of some sort. A robot is collecting the animals and begins to chase the man to collect him as well. The man tries various things to deter the robot but the robot is unstopable. Finally the robot catches the man and weighs him to find that because the man was running he lost weight and is no longer up to specification. The robot does not collect or freeze the man. Any idea let me know please.