MORE beavers?

A couple of days ago, someone found a beaver wandering around a Devon farm.  They called the RSPCA who, unused to the capture of beavers as a routine activity, accidentally chased it into a slurry pit, where it was apprehended and taken to Dartmoor Zoo to be cleaned off :  http://www.bbc.co.uk/news/uk-england-devon-17805465

( In which the mathematics of beavers proves more complicated than expected.  )