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burmese python vs. alligator.  Lori Oberhofer, National Park Service.  

A Burmese Python struggles with an alligator in Everglades National Park. Who will win? More...

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- by E.A. Zimmerman


We’ve all heard stories of pet baby alligators that were supposedly flushed down toilets and then grew to monstrous proportions, terrorizing the sewers of New York.  These particular tales may not be true, especially since it is unlikely that alligators could survive for any length of time in a sewer environment.  Sadly, other exotic pets have gone wild and established themselves where they were never meant to be.

Lionfish invades.
Non-native Red Lionfish, which probably escaped or were dumped into Florida waters, have been found off the coast of Jamaica, Cuba, the Bahamas, and even Long Island. Wikimedia Commons Photo by Jens Petersen

When some owners (or their parents, roommates or spouses) move, or grow tired of a pet that eats too much; gets too big; lives too long; costs too much to keep; is noisy; or is inconvenient because it smells nasty or makes a mess, they let it loose.  In some cases, as a result of an accident or natural disaster, exotic animals escape.  If they are able to establish themselves, they can wreak havoc on ecosystems, agriculture and the economy.  They can also harm human health and safety.  There are more than 50,000 alien species in the U.S. alone (source: NOAA). The ability of a population to survive and reproduce exponentially may not be apparent for decades.  By then, it is usually too late, too difficult and too expensive to reverse the damage.

A ubiquitous example is feral cats.  Thanks to a number of irresponsible cat owners, there are millions of homeless cats in the U.S.  These natural born killers pose a real threat to native wildlife.  They are not the only ones.  Tens of thousands of iguanas are breeding in Florida, where they have become a nuisance.  These large lizards munch on mangoes, berries, figs, tomatoes and bananas, in addition to bird eggs and nestlings.  They also dig burrows that undermine sidewalks and foundations, and spread salmonella through their feces.  

Burmese Pythons are breeding in the Everglades National Park and beyond.  Besides devouring cats and dogs, several endangered species have been found in the snake’s stomachs.  One 12.5+ foot python even tried to eat a 6.5 foot American alligator.  (The snake apparently exploded, prompting one reader to comment “My mom always told me never to eat anything bigger than my head. It looks like we have another case of poor python parenting.”)

Predatory Red Lionfish are invading the Caribbean, stinging divers and disrupting the delicate ocean ecology.  These natives of the Indian and South Pacific oceans were probably dumped out of fish tanks in Florida in the early 1990s, or may have escaped when a beachside aquarium broke open during Hurricane Andrew in 1992.  Like locusts, they have a voracious appetite.  A recent study found that five weeks after their introduction to an area, the survival of other juvenile reef fish populations plummeted by about 79% (Source: Science Daily)

In the 1960’s and 70’s, over 64,000 Monk Parakeets were imported to North America.  Monk Parakeets may be more appealing than slimy snakes, but the ones that got away are still creating problems.  Even though they are native to South America, they can live and breed in areas where temperatures go as low as -17 degrees Fahrenheit.  These squawking, aggressive birds construct communal nests the size of a Volkswagen. The nests are often situated in inconvenient locations like atop a power transformer. 

Dumping exotic animals into the wild is irresponsible.  It is also bad for the environment, and in some cases against the law.  To address the problem, some suggest recapturing the animals for the pet trade. However, there are not enough potential pet owners out there.  Also, some adult feral animals like iguanas and cats never tame adequately and rarely make acceptable pets. 

Other proposals include establishing or supporting centers that accept unwanted exotic pets, restricting sales, improving enforcement of laws, bounty programs, inserting identity chips in the animals so the dumper can be tracked down and fined, and banning importation or interstate transport (which might generate a black market). Not feeding wild exotics can help, as it attracts more of them and usually results in increased survival and reproduction. Smaller scale prevention initiatives may help control spread on the local level.  None of this will work without public support.  It is also critical to educate pet owners so they understand the damage they can cause.

Originally published in the Villager newspapers on September 26, 2008