ABC Wednesday: E is for Elephant Evolution

How are mammoths and mastodons related to elephants?

For this post I decided to do a double "E": elephant evolution.  Remember, if you have a favorite science subject, please let me know!

Many people believe that elephants descended from mammoths or mastodons.  This isn't true.  Elephants lived right along side mammoths and mastodons in different parts of the world for over four million years.

The family tree of mammoth, mastodons and Asian and African elephants.  In science, such a family tree is called a phylogenetic tree.  The different points where they branch off from each other are the points where they have a common ancestor.  Image from Reed College.

Mastodons are actually very different from mammoths and other elephants.  They are only distantly related.  Mastodons look like mammoths because they're big and hairy, but they're different in many important ways.  One of these are their teeth.

Mastodon teeth (left) and mammoth teeth (right.)  Mammoth teeth are almost identical to elephant teeth.  Both elephant teeth and mammoth teeth are very different from mastodon teeth.  From Kansas Geological Survey.

So mammoths and elephants are very closely related, but mastodons are only distantly related to both.

Recent research on mammoth DNA has also shown that mammoths are much more closely related to Asian elephants than African elephants.  

But all three - mammoths, Asian elephants and African elephants - walked the earth at the same time.  They're not descended from one another, but they all share common ancestors.

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So that was "E" on animals for photowannabe.  Next week: "F" on astronomy for PhenoMenon.