It's always been dogs for me. Since I was about 6-7 I was able to identify every dog breed (and I mean the rare breeds too. I remember correctly identifying Japanese Tosas, Catahoulas, Komodors, Leonberger, and Xoloitzcuintli long before my teen years, much to the owners' amazement), dog care, dog physchology, dog health and reproduction, etc. LOL! My intense interest when I was younger helped me become a well-known trainer of hunting hounds and sure has helped my job as a veterinary assistant.
Also have always been very interested in wildlife (specifically predatory mammals)--everything about them!