dominance

Question
My 1 1/2 yr. old spayed chocolate lab tries to hump dogs that are her own size. Why?  Is she trying to show dominance?

Answer
More like insecurity. If she was confident she would not have to go so far to prove it.

Or it could be learned. As in "everyone laughs when I do this". Either way, simply calling her away will reduce it-social distance is what she needs when she acts this way. It's her way of saying "I'm nervous".

Problem is, she does it to the wrong dog and they will take her face off for being inappropriate and you will have another potential problem.