For some people, owning a dog or cat isn’t nearly as exciting as keeping a tarantula or boa constrictor. However, many quickly learn that such exotic pets require far more maintenance than their bargained for. According to a new study, the biggest-selling exotic species are also the most likely to be released by their owners into the wild where they often turn out to be invasive species. In some cases, this can spell an ecological disaster.

A Burmese python found along the Shark Valley Road in Everglades National Park. Credit: National Park Service.

Julie Lockwood, a professor in the Department of Ecology, Evolution, and Natural Resources at Rutgers-New Brunswick, along with colleagues, tracked the trade of 1,722 reptile and amphibian species in the United States from 1999 to 2016. Because there are no comprehensive records, the team had to combine data from the United States Fish and Wildlife Service on live animals imported into the country as pets and a database that the researchers compiled themselves by scraping websites with records on reptile and amphibians sold in the US. 

The next step involved comparing this information with records of sightings of non-native species, which were gathered from published studies as well as citizen-science programs such as EDDMapS.

The researchers concluded that species with a high probability of being released into the wild were also imported at higher quantities. What’s more, these individuals had a relatively large adult mass and were initially sold at cheaper retail prices than species that were less likely to be released.

“The owners may underestimate the space and costs needed to keep such animals as they grow into adults. Boa constrictors and reticulated pythons grow over 8 feet long. African clawed frogs and Russian tortoises live 30 years or more,” Oliver Stringham, study lead author and a Rutgers doctoral student, said in a statement. “Not wanting to euthanize, owners may resort to releasing them instead.”

Once in the wild, exotic pets can destabilize ecosystems through predation, resource grabs, and disease transmission. Florida, for instance, is overrun by invasive and potentially invasive reptiles and amphibians. One of the most prominent of these new residents is the Burmese python, which appears to be a refugee of the pet trade. Another troublesome non-native is the Red Lionfish, which, according to the Fish and Wildlife Service, has been a direct threat to native saltwater fish in Florida since the late 1980s. It is believed that the root of today’s Lionfish infestation in the Atlantic Ocean resulted from an accidental release of six fish from an aquarium in 1992.

Since the first exotic creature was introduced to the state in 1863, 136 more non-natives have made a home in the Florida wild.

“There are several possible solutions that include everything from banning the import and sale of some species that are likely to be released and become invasive to widespread pet-owner education efforts. Most of these solutions have not been critically evaluated relative to how well they will reduce pet releases, and this is a clear research need going forward. I would recommend that owners seek to adopt out their pets using one of many conduits including ‘amnesty events’ and online pet classified ads. Although a very difficult ethical and personal decision, I would also recommend owners consider euthanasia,” Lockwood told ZME Science.

If you missed it over the weekend, check out this great story from Naples Daily News that highlights the work our Science Department's Burmese python research. #Science #Snakes #SciComm https://t.co/fSeyubJKJI

— Conservancy of SWFL (@ConservancySWFL) April 16, 2018

In many states, Florida included, it is illegal to release a non-native species without a permit. However, the law requires an officer with the Florida Fish and Wildlife Conservation Commission to physically observe the pet owner releasing the animal in order to prosecute them. As I’m writing this, no one has been prosecuted yet for dumping exotic pets into the wild. With this in mind, Lockwood and colleagues hope that a better-educated public — which includes buyers and sellers of exotic pets — will help curb the growth of invasive species in the country.

“Beyond research on which of the many policy solutions may be most effective at preventing pets from being released, I also think there is a need to better understand the role of pet importers and sellers in the production invasive former pets. There is also a need for wildlife agencies to better recognize the threat of released exotic pets to become invasive species. My suggestion to people considering buying an exotic pet is to pay attention to the maximum size and longevity of the species they are buying, and if they are unprepared to take on the care of an animal that reaches a certain size or lives for decades or more; buy another species,” Lockwood said.

The findings appeared in the Journal of Applied Ecology.