Good Animals Gone Bad: The High Cost of Invasive Species

By Heather W. Barron, DVM, DABVP

Hospital Director, CROW


An invasive species is defined as an alien species whose introduction does, or is likely to cause, economic or environmental harm or harm to human health. They typically affect native species through predation, habitat degradation and competition for shared resources and thus are one of the leading threats to native wildlife. In some areas, up to half of all threatened or endangered species are at risk primarily due to invasive species. Animal invaders rank second only to habitat loss as a threat to our native wildlife and ecosystems.

Invasive species of plants and animals costs the United States government BILLIONS of dollars every year. They are primarily spread by human activities, often unintentionally. People, and the goods we use, travel around the world very quickly, and often, unknowingly carry these uninvited stowaways with them. As global warming causes temperatures to rise, many of these species will continue to spread into areas where they were previously undocumented. 

^An invasive species from southeast Asia, the tokay gecko preys on Florida’s native geckos, lizards and tree frogs. 

Warm and sunny Florida is already home to an abundance of invasive plants and animals and the problems continues to grow. Florida consistently ranks in the top three states in the U.S. for number of nonindigenous species.

The Clinic for the Rehabilitation of Wildlife (CROW) is actively working to minimize the impact these animals have on us, our environment, and our native wildlife. For hospital admissions, our policy on these invasive animals has been shaped by Florida Fish and Wildlife Conservation Commission (FWC).

By law, invasive animals brought to CROW due to illness or injury are not able to be released back into the wild. In some cases, CROW is able to find captive or educational homes for these animals. However, in most cases, humane euthanasia is the only option available. CROW also works with local and state conservation organizations to help protect native species from the threats presented by invasive animals.

> Florida’s native southern toad (left) must compete for food with the invasive cane toad (right) from Central and South America. >

You can help too! Florida, for example, has approximately 200 different species of birds living here that are classified as “non-natives”. You can help manage this problem, by reporting sightings of non-native species to FWC. A new app for your phone, called IveGot1, makes combatting invasive species as simple as a few clicks. Easy species reporting captures your current location and allows you to submit an image of your sightings. IveGot1 allows for both online and offline reporting by enabling you to save reports on your phone to upload when network connectivity is available.

You can also help by never releasing non-native animals into the environment. Florida has an exotic pet amnesty day that allows you to surrender exotic animals to the state authorities with no questions asked.

You can learn more about invasive species by visiting CROW’s Visitor Education Center, where we have live animal exhibits of both indigenous and invasive wildlife. Visit for hours and program schedules. For more information on reporting invasive species, visit

< Visitors to CROW’s Education Center get to see and learn about “non-native” wildlife like the nine-banded armadillo, a species that has naturally emigrated into Florida. <