HIppos, Sunscreen, and Blood.

I was listening to someone with Alzheimers talk about hippos and how their sweat is red.  Most people tend to wave that type of comment away because its sounds like a figment of someone's imagination.

Being me, I checked the internet to see if it was correct.  It is sort of correct but not quite.

Here's the low down on it.  Yes hippos do produce a red "sweat" but it serves a purpose just like our sweat does but it is not designed to cool them down, it is designed to keep them from burning.   Yes, its a sunscreen among other things!

In addition, this "sweat" provides a covering that helps maintain its body temperature when submerged in water and discourages bacterial growth that could occur in the water.  The sweat is made up of two acids, one red and one orange.  The orange one is good at blocking the sun while the red one blocks the sun and is the one that inhibits bacterial growth.

On the other hand, horse sweat provides something different.  When a horse sweats, the sweat appears to turn into a lather of some sort.  The sweat itself contains a special protein called latherin which acts as a wetting agent that allows horses to sweat through a waterproof pelt.  This protein is also found in zebras, onagers, and asses.

If you look at the animal world in detail, you'll discover that not all animals have red blood.  Creatures who have red blood, have hemoglobin which is iron based so it turns red when exposed to air.  Other creatures have a different color of blood.   Animals such as spiders or horseshoe crabs have blue blood due to the amount of copper in the hemocyanin which carries oxygen much like hemoglobin in humans.  In this case, two atoms of copper combine with one oxygen molecule.

On the other hand,  sea cucumbers have yellow blood due to vanabin which a yellow based vanadium as a pigment.  It appears the vanabin does not transport oxygen so no one is quite sure what this pigment does but the blood is oxygenated.  Worms, have a unique green blood due to it having chlorocruorin which is a respiratory pigment.  In addition, the skink also has green blood but for an entirely different reason.  Its green blood is caused by a high concentration of  biliverdin which is a green pigment formed from the breakdown of hemoglobin.

Other creatures may have orange, purple, or colorless blood, all due to a different pigmentation.  Just to let you know, only one fish, the ice fish, has colorless blood because it lives in a very cold region.

I hope you found that as interesting as I did when I first read it.  Have a great day and let me know what you think.