The difference between mammoths and mastodons

I know there were prehistoric elephants out there called mammoths (and that they keep finding flash-frozen wooly mammoths in Siberia). I also know that there were prehistoric elephants called mastodons. What I don’t know, though, is how mammoths and mastodons are different. So what’s the difference between mammoths and mastodons?

The wikipedia article on Mastodons has a brief discussion of the differences between the two.

IIRC, mastodons had little “nipples” on their tusks, hence the name. Mammoths were smaller and had smooth tusks.

“Mastodon” means nipple TOOTH, not nipple tusk. Just about every museum has a display of a mammoth tooth next to a mastodon tooth.

Compare:
http://images.google.com/images?hl=en&q=mastodon+tooth&gbv=2
http://images.google.com/images?gbv=2&hl=en&q=mammoth+tooth

Mastodons were forest dwelling browers as seen by their teeth which were used for crushing soft leaves. Mammoths were steppe-tundra dwelling grazers as seen by their teeth which were used for shredding tough grasses.

They were just different species of elephant that differed from each other in lots of ways, just like African Elephants differ in many ways from Asian Elephants. Well, there used to be lots of different types of proboscideans but now we’ve been reduced to only two. I personally am heartbroken over this sad state of affairs.

This is tangential, but interesting: the mammoth is most closely related (based on mitochondrial DNA analyses) to the Asiatic elephant, and those two are most closely related to the African elephant. The poor mastodon remains an outgroup amongst the probiscideans, having diverged from the lineage that led to the other three ~24-28 million years ago.

Which is source of my faint (VERY faint) hope that maybe, one day, we will be able to clone if not mammoth, then at least mammoth-Asiatic elephant hybrid. That would be so cool.

Mammoths didn’t have big floppy ears, but elephants do. Are modern elephants evolutionary descendants of mammoths, or is there a disconnect?

They have a common ancestor, but the genetic lines connecting them are no less convoluted than the ones connecting us with other primates. =)
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