The previous episode, Season 3, Episode 10, has the on-screen title of "Curse Of The Kobra", while the on-screen title for this one is "Curse Of Kobra Part II". While skipping the "Part I" is understandable, so as to hide the two-part nature of this storyline, missing the "The" before Kobra is a clear goof (or alternately it should have been removed from Part I). During an interview about this story on the DVD, the staff briefly admit to this inconsistency.
The basic scheme of the villains centers around the "fact" that half-dinosaur people would be perfectly able to survive on a warmed-up Earth, while their main weakness is their lack of resistance to cold. However some dinosaurs were warm-blooded animals, some of which even thrived in arctic regions. Cold shouldn't be such an issue to the mutant dinosaur-men.