Do dogs temperature go up after running ?

No

Explanation:

After dogs run, just like humans because we are considered animals to, our bodies steadily decrease in temperature until the temperature reaches the regular body temperature. That's why dogs stick there tongue out and breath hard, they are trying to cool down there body temperatures, after of course they just did something to rise it. I Hope This Helps :)

I am pretty sure that they're temperature does go up because of the friction from running

Explanation: Dogs can also over heat from running in hot weather and my dog got a heat stroke last summer from laying in the sun for to long so be careful and make sure your dog(s) are/is hydrated!

not only is it colder, it also becomes darker, less salty, and more dense.

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!