Is a dog more sexist than a rat?

By now everyone in Canada has heard about Peter MacKay's alleged reference to former girlfriend and now Liberal MP Belinda Stronach as a dog during Question Period in Parliament yesterday. While admittedly being (or perhaps being admittedly) male precludes me from relating directly inflicted on Ms. Stronach, I can't help but wonder if it really represents a sexist attack, as so many opposition members have accused claimed.

To be sure, there are other words McKay could have used that definitely would have crossed the sexist line. But does referring to a woman as a dog do the same? Put another way, is a dog more sexist than a rat?

While being called a rat isn't an exclusively male experience, it's not often used to describe a woman. What if the tables were turned and it was McKay who crossed the floor? Imagine if the Liberal MP said something to the effect, "I smell a rat here," to which Stronach replied, "that's because he usually sits near you."

Would opposition members be calling Stronach sexist? Tactless, unprofessional, below the belt; mabe. But sexist? I don't know.