In "Longfellow" the reptillian race is represented are unassuming and inspiring for their hard-working nature and desire to overthrow their mammalian masters in the violet pachyderm race. This first work of pseudo-science fiction was notoriously panned in its day, but showed the creativity of the Northeast American.
In Twain's work, he represents Canadian-American life through animal races of all sorts, which ultimately leads to his own death. This however, does show a violent cultural side to Canadians that has been greatly downplayed over time.