I played with this one for a while. Some of the things said were done. I like the pose and the angle of his/her head. I would guess him but not sure!

I will be posting an image with natural window light that you might want to try. I love that type of light but it need a bit more kicker reflected back. Get yourself some white foam board or mylar reflector. I did not use it on this shot but it could have used one. Sometimes when our own animals are around, running for reflectors just loses the look we want.