Play animation if Player is close within certain distance.

Hey, I have a problem about play animation.
The script is not work. My animation just play a clip for a loop continuously without count distance when I Start the game.
How can I figure that?

using UnityEngine;
using System.Collections;

public class Penguin_ani : MonoBehaviour {
	
public AnimationClip clipName ;    
public float reachDistance;
public GameObject Player;
public GameObject Target;

	void Start () {
reachDistance =Vector3.Distance(Player.transform.position,Target.transform.position);
		if(reachDistance < 5.0f){
			      animation.wrapMode = WrapMode.Loop;
	  	          animation.Play(animation.clip.name);
	  	          animation[animation.clip.name].speed = 0.1f;
			      Debug.Log(reachDistance);
			
		}
		
		
	}
	
	// Update is called once per frame
	void Update () {
	
	}
}

Thanks for the help (:

do it in Update(){}