[identity profile] songster.livejournal.com 2012-05-20 09:38 pm (UTC)(link)
Depends which species of Smilodon: they ranged from half the size of Bullockornis to twice its size, according to Wikipedia at least.

[identity profile] sesquipedality.livejournal.com 2012-05-21 05:56 am (UTC)(link)
Clearly the one with the most badass Latin name (http://xkcd.com/1056/) would win.