They may be kept with the best of intentions, but exotic pets can create havoc at home and in nature.
Sometimes they turn on their owners, as happened to Kelly Ann Walz, 37, of Monroe County, whose husband was an exotic pet dealer for 14 years before his license expired in 2008. She was mauled to death Oct. 4 by a 350-pound black bear while cleaning its cage.
Mrs. Walz reportedly had thrown a shovelful of dog food to one side of the cage to distract the bear while she cleaned the other side, instead of putting the animal into a separate area.
That, experts say, was a case of a human disregarding basic rules of keeping wild creatures. Such incidents are relatively rare, they say, and tend to happen when owners grow so used to their undomesticated animals that they drop their guard.
"It's misplaced trust that the animal won't harm you because you have a relationship," said Jerry Feaser, spokesman for the Pennsylvania Game Commission. "Wild animals don't think that way."
Mark Henderson, who sells and breeds exotic birds and reptiles at The Enclosure in Plum, said his customers are intrigued by wild animals because of their beautiful colors and unusualness.
"Most of them know when they come in what they're getting into, but a lot do not," he said. "My job is to give them the proper education. It isn't for everybody."
People with permits, licensed dealers and menagerie owners are generally law-abiding citizens and not the ones the state worries about, Mr. Feaser said.
"It's the guy who gets an animal from Virginia, brings it back and nobody knows about it until it's a l60-pound mountain lion in a one-bedroom apartment."
Aggregate numbers are difficult to come by, but exotic pets represent a growing market nationwide even as the U.S. government prohibits importation of more wild species. Many are bred in captivity, circumventing the bans and giving rise to critics who consider the keeping of wild animals to be cruel and inhumane.
Owners have been known to release exotic pets into the wild when they get too big or troublesome to care for, menacing humans and native species. The animals may carry and spread disease that others have no defense against. They also may reproduce or cross-breed, upsetting the local ecological balance.
Burmese pythons set free by their owners have invaded the Everglades, where they multiply, kill pets and threaten people. A U.S. Geological Survey report released this month said five giant, non-native snake species pose a high risk to wildlife, especially in Florida, where some 270 pythons were removed from Everglades National Park alone.
In addition, Chinese snakehead fish, which breed rapidly, kill other fish and are said to be able to "walk" on land for short distances on their fins, have taken over bodies of water in Maryland and elsewhere. In Maryland, the snakehead fish was traced back to a home aquarium owner.
There's not much regulators can do about people illegally dumping pets into the wild except fine them if they're caught doing it. But Pennsylvania is one state that is trying to closely control and monitor the buying, selling and keeping of exotic species.
The state's Game Commission code spells out the rules governing mammals and birds. Snakes and other reptiles, fish and amphibians fall under the Fish and Boat Commission.
Under the Game Commission code, owners must have a permit to keep exotic pets at home. As of 1999, the permit requires proof that ownership is in line with all local ordinances. As of 2002, it requires proof of two years hands-on experience with that animal. Also mandatory is an inspection to ensure that housing arrangements protect the animal's welfare and the public safety. Permits must be renewed every year.
Mr. Feaser, of the game commission, said the tightened rules have reduced exotic pet permits. Before 2002, the state had 25 exotic wildlife dealers; today it has eight. Possession permits have dropped from 91 to 27, and permits for menageries -- where wild-by-nature animals are kept for exhibition -- have dropped from 144 to 103.
Still, he said, Pennsylvania's best efforts are undercut by nearby states.
"Ohio, Virginia and some others are very lax in their rules and regulations," he said.
Pennsylvania residents who can't legally obtain certain species will simply cross state lines, get the animals they want and smuggle them home. That's what happened with the 160-pound mountain lion, which was discovered in the small apartment across from a shopping mall in Dauphin County.
Also a problem are wolf hybrids, which are part dog but exhibit a wolf's wild nature and strength. They have been discovered living as pets with people in Chambersburg, Erie and Philadelphia.
Escaped exotic pets sometimes make news. In 2002, an Asian bearcat known as a binturong showed up on an unsuspecting homeowner's front porch after fleeing his Beaver County owner, who had bought him as a baby -- illegally, it turned out. "Binny" was sent to the Pittsburgh Zoo & PPG Aquarium.
In Pittsburgh, there was the famous 2001 case of Mr. Bigglesworth, a 42-pound African serval cat that escaped twice from his Point Breeze owner before being confiscated by the game commission.
"Normally, we don't know about these cases unless somebody reports them," Mr. Feaser said. "If someone smuggles in an African lion, eventually the neighbors will call us."
Primate ownership is illegal in Pennsylvania as of 2007, except for educational and institutional facilities. But the game commission has no jurisdiction over farm animals, livestock or equine species.
"If someone wants to own a buffalo or zebra, they don't need anything from us," Mr. Feaser said.
There's nothing new about imported species threatening native wildlife. In the 1800s, the European starling and the English sparrow were brought to Central Park, where they bred and became competitive with native blue birds for nesting areas.
When it comes to cold-blooded species, the state has no exotic pet regulations akin to those for birds and mammals.
"Right now we only regulate native species," said Bob Morgan, a conservation planning biologist for the state Fish and Boat Commission, and those rules are designed to protect endangered animals and plants. For example, the timber rattlesnake is considered threatened, so hunters need a permit to collect the limit of one per season.
Yet state residents may own all sorts of exotic fish, amphibians and reptiles without a license. One exception is the snakehead fish, which is completely banned in Pennsylvania.
Pets of tropical origin, such as pythons and boas, can't survive a Pennsylvania winter so they don't pose a danger of colonization if released. But they can still harm native species while they're alive, and they have been known to attack family members if they get loose at home. In 2002, an 8-year-old girl from Irwin was strangled to death after the family's pet python got out of its cage.
"We do not have exotic reptiles eating dogs here the way they do in Florida," Mr. Morgan said. "Although there was a good-sized alligator found in Allentown recently."
Mr. Henderson, the pet dealer, said that most owners are responsible, but there are exceptions.
"When I buy a motorcycle, I know what it's capable of, but does that mean I'm not going to get killed? No. There's a human factor."
Sally Kalson can be reached at firstname.lastname@example.org or 412-263-1610.