hippopotamus, hippo, river horse, Hippopotamus amphibius
['black swan, Cygnus atratus', 'African grey, African gray, Psittacus erithacus', 'American Staffordshire terrier, Staffordshire terrier, American pit bull terrier, pit bull terrier', 'hammer', 'ear, spike, capitulum', 'Rottweiler', 'Newfoundland, Newfoundland dog']