Why did the Sloth Cross the Road?

TO FLY!!!

http://www.youtube.com/watch?v=ba7rRfKIHxU&feature=related

Not that you care, but the reason his back became so rigid at 0:21 is that they have an extra set of articular surfaces on the vertebrae[*]....kind of the same purpose as the Flyin' Miata butterfly brace.

These guys are similarly equipped:

http://www.archive.org/details/morphologyofxena41gaud

• • sometimes even additional processes

interesting to know they can make their back rigid like that

In reply to JoeyM:

I don't know what the hell that thing is(I clicked the link but my eyes glazed over after the first sentence), but please tell me it's native to Austrailia or New Zeland???

petegossett wrote: In reply to JoeyM: I don't know what the hell that thing is(I clicked the link but my eyes glazed over after the first sentence), but please tell me it's native to Austrailia or New Zeland???

The first picture is a Pink Fairy Armadillo. It is about the size of a mouse.

http://en.wikipedia.org/wiki/Pink_Fairy_Armadillo

Did somebody say pink fairy?

1st: pink fairy armadillo
2nd: two toed ant eater

wiki is where I snagged the pics, and they have a description that is closer to jargon-free. "The name Xenarthra means "strange joints", and was chosen because their vertebral joints have extra articulations and are unlike those of any other mammals", or, you could go with my explanation, " "those things have some totally weird bones in their spine."

petegossett wrote: I clicked the link but my eyes glazed over after the first sentence

Sorry about the first link. Here's a quick translation: "These things have weird bones. We all know that, but until now, nobody has explained how totally weird they are. We cut up some armadillos to find out, and I'd like to tell you about what we saw. Hopefully, that will give everybody a decent a guess what is/was going on with the weird bones of related critters and fossils of old ones..."

(Grad school: a place where they teach you how to say simple things in the most complicated manner possible, supposedly for the sake of clarity.)