I don't know what it is with little Dogs, they all hump everything in sight plus they think their little Bad Azzes! I have a female Boxer and a female mini Dachshund (Wienie Dog), and the Boxer acts fine but my Dachshund acts just like that little Chihuahua did growling and acting like she's going to bite your head off! And she humps my female Boxer all the time,it's to funny looking!!