I agree, you have captured the moment very well and the composition expresses the intrigue our furry friends have with things that move.
I like this,it is a challenging shot with DOF versus shutter speed/aperture/ISO etc to capture this without resorting to flash.
I would prefer greater DOF so that more of 'fluffy' could be in the DOF...but with f1.4, full frame sensor and fast enough shutter speed... we will have to wait for some future generation technology I guess?
This is just my 'hang-up' due to having many 'stock photo' shots rejected because of "insufficient focus" etc. etc. so.... crisp focus and DOF are not necessarily the most important criteria.