I think that it was intentional at first, with the intent that the editors etc. would not catch that they are different species of snake. What I think happened was the main author people did it on purpose and the editors did a Google search and said "close enough".
Not to change the topic a tad, but the news is always out to try and spread fear... Especially about things people don't know.
http://www.local10.com/news/girl-bit...davie/27095208