Why is Piss Yellow?

As I was sitting on the commode this morning debating the pros and cons of photographing one's shit within and without its accompanying urine I suddenly wondered, "Why is urine yellow?" My first thought, of course, was that the intelligent designer made it so to keep it in the same color family as shit.

A quick google search answered my question. And it turns out the colors of shit and piss are related!

From the Science in Action blog:

The yellow color in urine is due to chemicals called urobilins. These are the breakdown products of the bile pigment bilirubin. Bilirubin is itself a breakdown product of the heme part of hemoglobin from worn-out red blood cells. Most bilirubin is partly broken down in the liver, stored in the gall bladder, broken down some more in the intestines, and excreted in the feces (its metabolites are what make feces brown), but some remains in the bloodstream to be extracted by the kidneys where, converted to urobilins, it gives urine that familiar yellow tint.

Surprisingly the article gives no credit to a designer, intelligent or otherwise!

But an argument can be made that photographing one's feces in a urine-free setting is unnatural. The bilirubin byproducts in the piss and crap want to be reunited.