They are never called that way in the dialog, but the only logical explanation is that Terra Nova is set in a parallel universe and the Time Portal is a wormhole between our universe and this parallel universe. So, it is not actually timetravel.
I think it is very confusing to readers when the articles use terms like "time travel", "time portal", "future", "alternate timestream" etc. while that is not actually the case.
I think it is better if we stopusing these words and call the animal by its true name. However, we'll have to deviate from words that are used on screen. I think that the increased clarity it offer will help a lot.
opinions?