…bored teenager, night of a riverside party? Neither was anywhere in sight.

 Really, I’m not kidding. Don’t know the first thing about beavers, except they’ll menace you with that SMACK if you get near their dam.

I vote  Beave  just  because  I  don’t  see  a  yoot  having  that  much  patience.  Beavers  are  busy,  and  they  are  also  patient.  But I defer to the authorities.