Before I agree to rent to anyone with an animal(companion, assistive or pet, I meet it to make sure it is not overly aggressive.

No evidence of animal or human waste on the walls or floor;11. 

Interesting issue, seems as though it may be similar to a service animal?

The cost in flooring damage alone from their animal dictates it.Although, it sounds like it's resolved now - good job!

We gave the guy a good portion of his security deposit back before he stormed off and we can do the rest of the walk-through.We found deep gouges in the walls due to moving, our lead-glass cabinet was broken, and the ground upstairs is soaked in animal excrement that will require redoing the hardwood floors.To be completely honest we would like to sue him over all of these repairs.

I haven't listened to this, but you might want to check it out:https://www.biggerpockets.com/renewsblog/2015/09/1...Student housing is a different animal.  

Do I need to tweak my contract to address service animals?

Now buying a property that is vacant is a whole nother animal.

Giving ordinary people homes in traditional housing developments that are advanced - green, clean, healthy, livable, walkable, integrated wtih the natural communities of non-humans (plants and animals).

When it comes to paid search ads, this is a different animal altogether and takes a lot of optimization and marketing knowledge.