boa constrictors

Question
My students are reading a novel where a 14 foot boa swallows a mule.  They are wondering if this is possible.  One of the boys says a boa can swallow an elephant - and we think he is nuts.  

Answer
Well, first off, neither boa constrictor constrictor nor boa constrictor imperator (the two types of boas that everyone is familiar with -- the "red tailed boas" that are for sale in pet stores) very rarely exceed ten feet in length and have an absolute maximum size of twelve feet.  A twelve foot BCC or BCI would weigh roughly fifty lbs.  An adult miniature donkey weighs between 200 and 350 lbs with mules weighing a good deal more.  Now, if this seems to pose a problem to you, it should.  

Boids (constrictors) in general do best on prey items that are only roughly as large around as the widest part of the snake's girth and BCCs and BCIs are actually extremely prone to regurgitation (which can be life threatening) if they are fed a prey item that is too large.  A hypothetical fourteen foot boa would probably only be able to eat large rabbits without making itself potentially quite sick.  

However, there is another possability: water boas, or anacondas, can and do take extremely large prey items.  An average sized adult green anaconda female will be about sixteen feet (with the record holding female coming in at 37.5 feet) and while an average sized female would still be eating chickens and flemish giant rabbits (they can get up to 25 lbs), a large female could quite possibly eat a young mule.  So the book is off, but there is at least some truth to the notion of a snake eating a mule.  

As for elephants, well, I'm afraid the child who believes that might need to take a trip to the local zoo so he can look at an elephant and then look at a large snake.  It might give him some perspective on size.  

I hope that helps!  :)