__________Q__________
     /                     \  
 fish   ____________________Q______________________
       /                                           \
      Q                    _________________________Q___________________________
     / \                  /                                                     \
   cat dog      _________Q__________                                _____________Q_______________
               /                    \                              /                             \
          ____Q____             _____Q______                 _____Q______                   ______Q______
         /         \           /            \               /            \                 /             \
        Q           Q         Q              Q             Q              Q               Q               Q
       / \         / \       / \            / \           / \            / \             / \             / \
     cow horse sheep wolf frog wolverine seal badger walrus ocelot hamster gerbil platypus unicorn pegasus axolotl