Nobody puts Venice rats on a postcard. Still, ask the people who deal with them for a living, and you’ll hear the same thing right now: there are more of them than there used to be. And the reason is so odd that I had to read it twice. Venice did something right, and the rats are the ones cashing in.
Venice rats and the flood barrier: what’s going on?
For centuries, acqua alta, the high water that creeps through the city, did more than soak Piazza San Marco. It also flooded cellars, drains and low-lying corners where rats like to nest. Young ones drowned, and adults were pushed out of their hiding places. Not pretty, but effective.
Now the city stays dry. According to Il Post, that natural brake is gone. Filippo Roncali, technical director of the pest-control company Veneziana Disinfestazione, told the local paper La Nuova Venezia that the rat population has objectively grown. The culprit, or hero, depending on your view, is a flood barrier called MOSE.
What is MOSE, and since when does it work?
MOSE stands for Modulo Sperimentale Elettromeccanico, and yes, the name is also a wink at Moses parting the Red Sea. It’s a system of 78 mobile gates sitting on the seabed at the three entrances to the Venetian Lagoon: Lido, Malamocco and Chioggia. When a high tide is forecast, compressed air empties the gates; they swing up, and the lagoon is sealed off from the Adriatic. Raising them takes about 30 minutes.
Construction started in 2003, and it took a very long time. Delays and a corruption scandal in 2014 pushed the finish line back again and again, and the price tag is estimated at around 5.5 billion euros. The first full test happened in July 2020. On 3 October 2020, MOSE was raised for the first time against a real flood and kept St Mark’s Square dry. If you want the full technical background, this MOSE overview is a solid read.
It’s working hard, by the way. In 2026, the gates went up 30 times, all between 28 January and 20 February, because water levels were unusually high.
Why a dry city is a paradise for rats
Rats breed fast. Fast as in: up to seven litters a year, three to 15 pups each, with a pregnancy of around 24 days. The females can get pregnant again roughly 18 hours after giving birth. Once the pups are about a month old, they head off on their own. Without regular floods interrupting that cycle, the maths gets uncomfortable pretty quickly.
Two species live in Venice. The brown rat, the pantegana, nests near the ground and sticks to canals and busy areas. The black rat is the more common one and a great climber that prefers dry spots, which makes the dry, rat-friendly Venice of today a pretty comfortable home for it.
Do tourists make the Venice rat problem worse?
Probably, yes. Il Post points to a report in L’Identità saying that tourism produces lots of food waste in the alleys, which gives the rats plenty to eat. No numbers, so I’d treat it as a contributing factor, not the whole explanation. Still, it doesn’t take a pest-control expert to see that a dropped slice of pizza in a narrow alley isn’t helping.
Will you actually bump into a rat on your trip? Honestly, I think most visitors never will, and I wouldn’t cancel a Venice weekend over this. What I would do: bin your leftovers properly, eat at a table, and not feed the pigeons or anything else. If you’re planning a day trip, check the current entrance fee for tourists in Venice first, and have a look at what else has changed for travellers in my overview of what’s new in Italy in 2026.
Venice has been outsmarting water for a thousand years. Outsmarting rats might turn out to be the trickier job.
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