There were other passengers". However, the animal fell foul of a ticket inspector alerted by the tram driver.
Frontier's current policy bans "unusual or exotic animals", including "rodents, reptiles, insects, hedgehogs, rabbits, sugar gliders, non-household birds or improperly cleaned and/or animals with foul odor".
The Romans used dead animals to foul their enemies' water, and the bodies of infected soldiers were catapulted into besieged towns in medieval times.
It could also bring unwanted attention if sailors fall ill or if floating rubbish – plastic bags to door frames to animal carcasses – fouls rudders and costs someone an Olympic gold medal.
The men who relieve themselves in public against a city wall, the dog-owners who allow their animals to foul the pavements, the smokers who throw their cigarette ends on the ground, the litter-bugs; just listing them is guaranteed to bring public-spirited dwellers of the French capital out in a cold sweat.
"Cormorants, gulls, pigeons, pelicans and other animals have fouled the area," Mayor Bob Filner wrote last month in a memo, declaring a state of emergency.
It killed an estimated 3,500 sea birds and an incalculable number of marine animals and fouled the undersea vegetation, which in turn caused untold damage to the food chain for many years.
Dogs immediately began barking again, and the foul animal odor entered the room almost shockingly.
Run-off from animal manure also fouls watercourses, and the release of nitrous oxides from uncovered dung heaps pollutes the air.
Nor does Mother Nature limit her revenge to those who are cruel to animals or who foul her atmosphere.
