As anyone who owns gerbils or has owned gerbils would know, the little fluff balls do not stay still for very long. This photo has captured one of the adorable, energetic rodents perfectly. This one probably dashed off the second the photo was taken, it looks pretty much ready to do so here. Those gleaming eyes are definitely an indication of a very healthy little gerbil.
The focus on the image is solely on the gerbil and the immediate area it's standing on. It draws your eye towards the animal. Particularly as the complimenting light in the photo almost make the gerbil look like it's smiling.
The monochromatic format of the photo blends the tones of the picture a little, (and I find it a little disorienting) however, that means there's less visible things in the background to draw your eyes away from the subject (the gerbil).
There are a lot of black and white photography out there, however this one stands out as it involves a rodent, there are few dramatic images out there of rodents in black and white.
Overall, I think it makes even something as cute and occasionally amusing as a gerbil look dramatic and pretty stunning. It definitely captures the pure character of the little animal and the black an white almost exaggerates it.