Views: show only one node per select box value
I thing it's difficult to make just with the views UI (the aggregation will not work)
If you don't want the solution of Anil Sagar, i have another solution with some theming.


Go to format =&gt; setting : In Grouping field Nr.1 select your field type (left)
Now your result will by group by type (dog, cat and others) You can see an extrat of the output. (right)





Go to Advanced setting =&gt; Other =&gt; Theme information





Copy / Paste views-view-list.tpl.php in your new template and make some modification   

 &lt;?php print $wrapper_prefix; ?&gt;
 &lt;?php if (!empty($title)) : ?&gt;
   &lt;h3&gt;&lt;?php print $title; ?&gt;&lt;/h3&gt;
 &lt;?php endif; ?&gt;
 &lt;?php print $list_type_prefix; ?&gt;
 //Add this
 &lt;?php $x = 0; ?&gt;
 &lt;?php foreach ($rows as $id =&gt; $row): ?&gt;
    &lt;?php if($x &lt; 1): ?&gt;    
    &lt;li class="&lt;?php print $classes_array[$id]; ?&gt;"&gt;&lt;?php print $row; ?&gt;&lt;/li&gt;
    &lt;?php $x++; ?&gt;
  &lt;?php endif ?&gt;  
&lt;?php endforeach; ?&gt; 
&lt;?php print $list_type_suffix; ?&gt;
&lt;?php print $wrapper_suffix; ?&gt;



And you'll have what you wanted: