Passengers on a WestJet flight headed from Toronto to Vancouver were forced to leave the plane on Saturday night for possible safety concerns after some unwelcome guests made it onto the aircraft.

Reports on social media by some passengers Saturday night detail their surprise and amusement to find that the culprits were iguanas on the loose.

The plane arrived in Toronto from Cuba earlier Saturday. Passengers had disembarked and were making their way through customs when one of them was stopped because an iguana was found in his checked luggage, WestJet spokeswoman Lauren Stewart told CBC News.

The man admitted to having brought four such critters with him. But when he searched his bag, he could find only two. The other two, staff presumed, must have escaped onto the plane, which by then had been boarded by passengers on Flight 723 departing Toronto for Vancouver.

Iguanas loose on a plane in Toronto? Where's <a href="https://twitter.com/SamuelLJackson">@SamuelLJackson</a> when we need him?! <a href="https://twitter.com/hashtag/WestJet?src=hash">#WestJet</a> —@bloginhood

One passenger tweeted that a stewardess said a man had attempted to smuggle the iguanas on his body and that some had escaped.

Iguana update: a stewardess told a guy next to me that apparently some dude on our plane tried to smuggle several iguanas aboard on his body —@bloginhood

...some of them supposedly escaped when he tried to transfer them to his carry-on....<a href="https://twitter.com/hashtag/WestJet?src=hash">#WestJet</a> <a href="https://twitter.com/hashtag/AirIguana?src=hash">#AirIguana</a> —@bloginhood

Stewart confirms that the iguanas likely found their way out of the man's baggage. And while they probably didn't get beyond the plane's cargo area, airline staff didn't want to take any chances of the critters possibly chewing through any wiring.

Stewart wouldn't say how many passengers were on the plane but said the entire aircraft was cleared out "to make sure there were no safety issues."

The plane had to be fumigated to ensure the lizards were gone.

The delay lasted 50 minutes in total, she said, at which point passengers boarded a different aircraft, then set off for Vancouver.

We have now boarded the new plane & are awaiting takeoff... without any reptilian livestock.<a href="https://twitter.com/hashtag/WestJet?src=hash">#WestJet</a> <a href="https://twitter.com/hashtag/AirIguana?src=hash">#AirIguana</a> —@bloginhood

That was welcome news to some passengers, but left others questioning how the lizards made it past security in the first place.

Stewart says the plane remains out of the air until staff can confirm there are no creatures on the plane.

Asked if the airline had encountered any such incidents before, Stewart replied that she spoke with operations staff. "Apparently, it's not common at all," she said. "They haven't heard of this before."