Birds are my favorite animals. The different bird flight techniques, thermal vs. dynamic soaring employed by raptors, and constant wing flapping only done by a few big sea birds amaze me. There are birds like a frigatebird that can stay aloft, flying constantly without touching the ground, for more than a week. A bar-headed goose can fly higher than the Mt. Everest where people and other animals will die immediately for lack of oxygen. Some birds can walk, run, swim and fly all at the same time, some can walk and fly only, and a few can only fly but neither can walk nor swim. I find all these different nature, flight mechanism, and adaption of birds fascinating.
Pretty much any animal with fur and a cute face.
Dogs, cats, wolves, bears, rabbits, lions, tigers, cheetahs and so on.
I've always wanted a bear as a pet.