Visible Breath

I finally got an answer to one of the questions of an earlier post: why can you see a whale's breath even if you can't see your own?  Their body temperature is the same as ours, and often the local humidity is the same (like the humans are on an open boat.)  A grad student running a whalewatch boat gave the answer as being size-related: whale lungs are so much bigger than ours, that even a slight haze is visible.  But I was still suspicious; people have made up answers to this question before.  (See the comments on the earlier post.)  Her answer sounded reasonable, but maybe still wrong.

But now we have proof, at least corroborating evidence.  Dogs in Philly range in size from "fuzzy slipper" to "Marmaduke,"and when they gotta go out they gotta go out, even if it's cold.  Under certain conditions you can see the breath of big dogs but not little ones. Case closed.  I also remember a few times when it's been cold enough to see a bird's breath, but that's pretty unusual and I was also the only person outside to see it.

Note also that breath requires high humidity in order to be visible.  It can be really effing cold in the desert and  you still can't see your breath, or coldish room temperature in Volcano Village and you can.  But in this case, the dogs can be right next to each other and the effect still holds.

Randomly: colder air is dryer.  So is it ever so cold that you can't see your breath?

Addendum: Irl in the comments confirms that the answer is no.  Also the 300 Club.