Oh, I thought you meant your companion, apologies. Indeed, you can't have any intercourse with other animals/mutant animal-like creature, other than the dog companion that you obtain by rescuing. But it would be quite interesting if they added it to the game.
I tried to play the offline version, but it didn't work.. I had to wait 30 minutes for expectation, before disappointingly closing the program.. How do I fix this if I may ask?