Oleg Zabluda's blog
Friday, November 09, 2012
 
- Doctor, my wife cheats on me, but I don't grow horns.
- Doctor, my wife cheats on me, but I don't grow horns.
- It's just a figure of speech.
- Good. I was worried I have calcium deficiency.

This anecdote is factually correct, horns, antlers, bones are calcium carbonate (CaCO2, same as chalk), rigid but brittle, on collagen, flexible but bendable. Combination is a composite material, light and strong.

However, many people think that one needs calcium for nails and hair. That is a total myth. Hair and nails are made entirely of protein keratin (similar to collagen), as well as hooves, outer layers of skin, hedgehog quills, bird feathers and beaks, and scales, all of the above ultimately evolved from, and have no calcium whatsoever.

Another tough biological substance is Chitin, but unlike protein keratin, it's a polysaccaride cellulose. It is the main component of the cell walls of fungi, the exoskeletons of arthropods such as insects and crustaceans, the radulas of mollusks, and the beaks of cephalopods, such as squid and octopus.

Mollusk shells consists of mainly chitin and conchiolin (a protein) hardened with calcium carbonate.

In 2011, scientists were successful in sequencing 11 fragments of collagen recovered from the fossilized bones of a 68-million-year-old Tyrannosaurus rex and an 80-million-year-old Brachylophosaurus canadensis. That was the first definitive proof that birds evolved from dinosaurs.

http://en.wikipedia.org/wiki/Cuckold
http://en.wikipedia.org/wiki/Collagen
http://en.wikipedia.org/wiki/Keratin
http://en.wikipedia.org/wiki/Fibrous_protein
http://en.wikipedia.org/wiki/Chitin
http://www.nature.com/news/2011/110614/full/news.2011.369.html
http://en.wikipedia.org/wiki/Cuckold

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