BALLIVOR, Ireland » Legend has it that St. Patrick drove all the snakes out of Ireland. The economic crisis has brought some of them back.

During the Celtic Tiger boom, snakes became a popular pet among the Irish nouveau riche, status symbols in a country famous for its lack of indigenous serpents. But after the bubble burst, many snake owners could no longer afford the cost of food, heating and shelter, or they left the country for work elsewhere. Some left their snakes behind or turned them loose in the countryside, leading to some startling encounters.

A California king snake was found late last year in a vacant store in Dublin, a 15-foot python turned up in a garden in Mullingar, a corn snake was found in a trash bin in Clondalkin in South Dublin, and an aggressive rat snake was kept in a shed in County Meath, northwest of Dublin, an area dotted with sprawling houses built during the boom.

"The recession is the thing that’s absolutely causing this," said Kevin Cunningham, a 37-year-old animal lover who started the National Exotic Animal Sanctuary after he left his job at a Dublin nightclub. He has transformed an old single-room schoolhouse near Ballivor, a hamlet in the Meath countryside, into a reptile sanctuary.

"It was about status," Cunningham said as he waved to a 4-foot red iguana that was found under a sink in an abandoned house in Dublin. "During the boom, people treated these animals as conversation starters."

Animals have always been abandoned in greater numbers in times of famine, economic hardship and mass emigration in Ireland, but in the past that usually meant farm animals. The Dublin Society for the Prevention of Cruelty to Animals was taking in five or six emaciated horses a week as recently as 2010. Now, though, snakes are more common among the foundlings, including a python named Basie that someone recently dropped by the side of a road.

"In the Tiger economy," said P.J. Doyle, a reptile expert, "young people could pay 600 quid for a snake" and the necessary equipment — about $700 to $1,000 during much of the boom. But these days, he said, some owners "just drive up and throw them somewhere."

Doyle, a hulking man with weathered skin and a gap between his teeth, helped the DSPCA brace for an influx of reptiles around, of all dates, St. Patrick’s Day, when the warmer spring weather means that the coldblooded snakes will be more active and more likely to show themselves.

"We always get a bump in calls around Paddy’s Day," Gillian Bird, the education officer at the DSPCA, said as she pet Carl, a green iguana from South America that she named after a colleague’s boyfriend.

Irish legend holds that the country has no native snakes because St. Patrick banished them in the fifth century. But science says the country was snake-free long before Patrick’s time. When the glaciers of the most recent ice age retreated from the British Isles more than 10,000 years ago, Ireland was already separated from the rest of Europe by open sea, an isolated ecosystem with a damp, chilly climate that is hostile to almost all reptiles, other than a common lizard.

Most of the recent snake sightings have occurred in the counties around Dublin, where the newly prosperous congregated in the country’s boom years. The government does not require owners to register pet reptiles, so there are no official statistics on the total number of snakes present in the country.

"If you buy a dog, you need a license, but if you buy a snake, you don’t," said Brendan Ryan, a director of the Irish Pest Control Association.

Like the country’s housing boom and subsequent bust, the snake influx can partly be traced to European integration. In the years when Ireland stood somewhat apart from the broader European economy, it had strict regulations on the types of plants and animals that could be imported, but now Ireland’s standards match the more relaxed rules of other member states of the European Union.

"We’ve got no regulation whatsoever covering exotics," said James Hennessy, zoo director and founder of Reptile Village conservation zoo in County Kilkenny. "Once it’s in Europe legally and coming from other European states, you can pick up whatever you want."

Reptile Village is often called upon to rescue animals, including a crocodile that had been bought online and then abandoned in a Dublin apartment and a 6-foot boa constrictor that had taken up residence under a skylight in an attic in County Meath. "His name’s Sammy and he’s brilliant," Hennessy said of the snake.

A spokesman for the Department of the Environment said Ireland adheres to the Convention on International Trade in Endangered Species. But the convention does not prohibit trade in venomous snakes, which, while still rare here, can legally be bought in Ireland. That presents a scary proposition in a country with almost no antivenin stocks.

"You have to ask yourself why it’s permissible to have these animals in the country," Ryan said.

Though a few loose rattlesnakes, cobras and vipers have been reported, most of the released snakes are not venomous and pose little or no hazard to humans. That doesn’t always make them a welcome sight, though. "We have it deep inbred in us that they’re evil and nasty and tempted Eve and were led out of Ireland," said Cunningham, the animal sanctuary founder.

He said one 6-foot snake ended up with him recently after its owner lost his job and had to move in with his parents: "Being a good Irish mother, she said, ‘Of course I’ll take you back home — but I’m not taking your boa constrictor."’

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