The 43-year-old actor, who left his role as palaeontology expert Nick Cutter in the last series, told the Chester Chronicle that he can understand why the dinosaur drama has proved so popular with fans.
"I thought that the writing was good enough and the premise was good enough, [and] if people liked it, it could go pretty much as long as it liked," Henshall explained.
"As long as people had faith in it who were making it, then I thought it would be fine. It taps into an eternal thing in young people, dinosaurs, monsters and myths and legends."
He continued: "I went to the Natural History Museum the other week with my niece, she's in her twenties, she's not a kid, but we had to go down there because I thought she should see it. Me and my partner, the three of us were walking through the dinosaur exhibit and kids, boys and girls were queuing and queuing to see this big Tyrannosaurus Rex and you think, 'What is it about dinosaurs?'."
Primeval was axed after three series in the summer. However, the show was later granted a reprieve thanks to a new co-production deal involving ITV, UKTV and international broadcasters.