 While choosing a species for Perry , Povenmire and Marsh wanted to keep in mind selecting one that was uncommon , an animal that kids could not " pick out at a pet store and beg [ their parents ] for . " They chose a platypus because of the animal 's obscure and striking appearance . The animal was scarcely used in American animated programs , so the pair opined that Perry " would not have to compete with <unk> notions that viewers might bring to a more conventional <unk> . " The blank storyboard they were given allowed them to " make stuff up " since " no one knows very much about [ them ] . " 
