Maybe the number sequence refers to gestation periods? As in 9 months for a human, 22 months for an elephant, 8 months for a hippopotamus... :lol:
In which case the answer would be "A Baby" 
I was thinking a dates too.
Alas the puzzle states: "Put all of them" .. So we are looking at a menagerie of babies...
Oh and the numbers 20 and 18 don't correspond to any gestation period known to me or my sources. (Unless you include a pre-mature elephant, and a VERY pre-mature elephant..)
I also had a look at labelling the various numbers as for instance 9 seconds, 22 minutes etc etc. Can't see anything that makes sense. I have a new theory. It is so obvious.
It is a girl from germany. And I have evidence:
http://profile.myspace.com/index.cfm?fuseaction=user.viewprofile&friendid=92282018Yes. Look at the friendid. It's a sign.
The URL have spoken.