Comparando elementos en una matriz multidimensional

Digamos que tengo una matriz multidimensional. Por ejemplo:

 Array ( 
         [0] => Array ( 
             [animal_id] => 5494 
             [animal_name] => "Suzy"
             [animal_type] => "zebra" 
             [animal_location] => 0 
             [animal_awake] => 1
             [animal_age] => 3 ) 
         [1] => Array ( 
             [animal_id] => 5494 
             [animal_name] => "Joshua"
             [animal_type] => "panda"
             [animal_location] => 5
             [animal_awake] => 0
             [animal_age] => 8 )
        [2] => Array ( 
             [animal_id] => 5494 
             [animal_name] => "Debra"
             [animal_type] => "snake" 
             [animal_location] => 7 
             [animal_awake] => 1
             [animal_age] => 3 ) 
        [3] => Array ( 
             [animal_id] => 5495 
             [animal_name] => "Caleb"
             [animal_type] =>  "zebra"
             [animal_location] => 0
             [animal_awake] => 1
             [animal_age] => 3 ) 
        [4] => Array ( 
             [animal_id] => 5495 
             [animal_name] => "Joshua"
             [animal_type] =>  "panda"
             [animal_location] => 5 
             [animal_awake] => 0
             [animal_age] => 8 )    
        [5] => Array ( 
             [animal_id] => 5495 
             [animal_name] => "Debra"
             [animal_type] =>  "snake"
             [animal_location] => 7 
             [animal_awake] => 1
             [animal_age] => 3 ) 
        [6] => Array ( 
             [animal_id] => 5496 
             [animal_name] => "Emily"
             [animal_type] =>  "zebra"
             [animal_location] => 0
             [animal_awake] => 1
             [animal_age] => 3 ) 
        [7] => Array ( 
             [animal_id] => 5496 
             [animal_name] => "Joshua"
             [animal_type] =>  "panda"
             [animal_location] => 5 
             [animal_awake] => 0
             [animal_age] => 8 )    
        [8] => Array ( 
             [animal_id] => 5496 
             [animal_name] => "Debra"
             [animal_type] =>  "snake"
             [animal_location] => 7 
             [animal_awake] => 1
             [animal_age] => 3 )             
         )

Y quiero comparar todas las serpientes contra las serpientes, y todos los panda contra el panda, etc. (pero no una serpiente contra un panda) y poner los elementos únicos en una matriz (todos los elementos únicos en una sola matriz), ¿cómo podría? ir haciendo esto Ya que son elementos dentro de una matriz, estoy un poco perplejo. Además, no sabré de antemano cuántos tipos diferentes habrá. Por ejemplo, una vez podría pasarme una matriz multidimensional con Panda, Bear, Snake - La próxima vez podría pasarme una matriz con Bird, Cat, Panda, Zebra.

¿Algunas ideas?

SALIDA FINAL

      Array ( 
     [0] => Array ( 
         [animal_id] => 5494 
         [animal_name] => "Suzy"
         [animal_type] => "zebra" 
         [animal_location] => 0 
         [animal_awake] => 1
         [animal_age] => 3 ) 
     [1] => Array ( 
         [animal_id] => 5494 
         [animal_name] => "Joshua"
         [animal_type] => "panda"
         [animal_location] => 5
         [animal_awake] => 0
         [animal_age] => 8 )
    [2] => Array ( 
         [animal_id] => 5495 
         [animal_name] => "Caleb"
         [animal_type] =>  "zebra"
         [animal_location] => 0
         [animal_awake] => 1
         [animal_age] => 3 )    
    [3] => Array ( 
         [animal_id] => 5495 
         [animal_name] => "Debra"
         [animal_type] =>  "snake"
         [animal_location] => 7 
         [animal_awake] => 1
         [animal_age] => 3 ) 
    [4] => Array ( 
         [animal_id] => 5496 
         [animal_name] => "Emily"
         [animal_type] =>  "zebra"
         [animal_location] => 0
         [animal_awake] => 1
         [animal_age] => 3 )    

     )