RayCasts and BoxCollider2D not working?

Hi, I'm having problems detecting a raycast with a BoxCollider2D. The object isn't marked as a Trigger, I'm using this code:

         void Update ()
         {
  
      
          
                 // Use Raycast to pick cards that have mesh colliders attached...
             
                 Ray ray = Camera.main.ScreenPointToRay (Input.mousePosition);
             
                 Debug.DrawLine (ray.origin, hit.point);
      
                 if (Input.GetMouseButtonDown (0)) {
                         if (Physics.Raycast (ray, out hit, 500f)) {
 
         
                                 Debug.Log ("Hit: " + hit.collider.gameObject.name);
                                 if (hit.collider.tag == "Pig") {
                                         animator = hit.collider.GetComponent<Animator> ();
                                         if (!animator)
                                                 Debug.Break ();
                                         animator.SetBool ("Flip", true);
                                 }
 
                         } else {
                                 Debug.Log ("Nothing there");
                         }
                      
                 }
         }

It never seems to return a collision (outputs 'Nothing there' in code below). The tags are setup up correctly, the object has a boxCollider2D.

Is there something specific I'm not address for boxCollider2D?

Thanks for any help!