There has always been a lot of discussion about this topic and the only references I can find are more arbitrary as well.
As the others have mentioned here: there is the "Behemoth" from the land (Job 40:15-24), which has been speculated as everything from a Hippopotamus to a Brontosaurus; and "Leviathan" (Job 3:8; Job 41:1; Psalm 74:14; Psalm 104:26; Isaiah 27:1 ) from the sea, which has been thought to be either a huge whale or a giant sea serpent of some kind, possibly even a Mosasaur-type dinosaur?
There were "Giants" in those days as mentioned in Genesis... and many Creationists hold the belief that the whole "carbon dating" thing is way out of scale in time frame because of the "Flood Layer" found in geological evidence as well as other factors. Not to mention the fact that going by Biblical sources, we would believe that God created life more instantaneously versus evolution over "millions" of years (or at least He speeded the process up quite significantly).
This does not surprise me with the scientific evidence of Dinosaurs actually living beyond their normal era, as in the Coelacanth for example and rumors of other things like "Loch Ness".
Maybe these are the animals that lived outside the Garden of Eden in the more "harsh" world from the beginning? It's one of those things we may have to wait and ask Him ourselves later!
Here is an interesting Hub however on the subject (and catches a lot of flak):
These kind of things are always worth keeping your mind open to. God CAN do anything He wants (and quite frequently does!).