The OOF bear is deliberate. The MAIN SUBJECT IS THE FOREGROUND GLASS.

Look at the glass. This was a reasonably "clean" section. Other areas had heavy dirt smudges that made photography close to impossible.

This image shows part of the reason WHY I HATE being forced to shoot through glass at a zoo.
What you see here is part of why resulting images (taken through glass) are never as crisp as a different photo (one shot with no glass in front of the subject) might be.

FYI, there is also a wide variety of finer scratches and marks on this glass than even this image can exhibit. However, the lens captures them. Therefore, image quality thus deteriorates.

Although I captured this image http://www.pbase.com/dpf/image/151124126 yesterday through this section of glass (with a mere bridge camera no less) the image ion this page will tell you why I HATE SHOOTING THROUGH GLASS!!

No, I did not make any major post editing changes to my final image at the link of the Polar Bear & Girl. I merely took care of most of the "glass problems" on site while using the camera.
Still, even with the best of camera work, a subject behind glass will never be as "clear" as a subject that is not behind glass.

Add reflections and dirt smudges to the image on this page. Each of these problems will then add up to explain why photographing a subject behind glass can be extremely problematic.

I HATE, HATE, HATE being forced to do photography through glass.