It is unlikely that Bernhard is a frog. There is a very good chance that Julius is a lion. There is a very good chance that Lily is a rhino. It is highly likely that if either 'Bernhard is a frog' or 'Lily is a rhino' but not both then Brian is a swan. There is a very good chance that if 'Lily is a rhino and Julius is a lion' then Jessica is a cat. It is highly unlikely that if 'Bernhard is a frog' or 'Lily is a rhino' or both then John went to the kitchen.
Chances are about even that either 'Julius is a lion' or 'Brian is a swan' but not both.
Chances are about even that either 'Julius is a lion' or 'Brian is a swan' but not both.
It is almost certain that either 'Julius is a lion' or 'Brian is a swan' but not both.

  and(A,B) :- A,B.
  or(A,B) :- A;B.
  nand(A,B) :- not(and(A,B)).
  nor(A,B) :- not(or(A,B)).
  xor(A,B) :- or(A,B), nand(A,B).

  %hop0
  0.2::factA.
  0.8::factB.
  0.8::factC.
  %hop1
  0.9::factX:-xor(factA,factC).
  0.8::factY:-and(factC,factB).
  0.05::factZ:-or(factA,factC).

  %hop2
  conclusion:-xor(factB,factX).

  query(conclusion).
  
Either 'Julius is a lion' or 'Brian is a swan' but not both.