I've seen this behavior at my house since I got my second Corgi and now I've seen it at the dog park about a dozen times.
At home - my dogs are not typically jealous of one another. If one is next to me and I'm petting him or her, the other takes no notice. However - if I pick one of them up, the other one goes nuts! Jumping and trying to nip at the legs of the one I am holding. I don't pick my dogs up very often, but when I'm going to brush them or give them medicine I casually walk over and pick them up and as I described before the other one goes crazy. It doesn't matter which one I'm holding, the behavior is the same.
At the dog park, I've seen a couple that had two little Toto type dogs. They picked one up for whatever reason and the other started jumping up to nip the heels of the one being held. Even one of mine jumped in - embarrassing.
Does anyone know what this behavior is or why it happens? Do they see the one being held as weakened in some way? Or is it in fact jealousy?
Am I the only one that's noticed it or is it common among multiple dog households?
Any idea on how to stop it? Both of mine are pretty good with "leave it" but for some reason it doesn't work in this situation. And it's hard to train them out of it because both of them are present and they're insanely excited when it happens.