Invasive Animals

Our nation’s national parks are managed to preserve unimpaired America’s natural and cultural resources. This mission is under a deep and immediate threat as a consequence of invasive animal species.

Despite these challenges, there are bright spots where parks are managing invasive species challenges, as well as opportunities for the National Park Service (NPS) to take a lead in addressing the threat. Successfully maintaining America's treasures - the national parks - will require coordinated and innovative action to manage invasive animal species. species. The NPS is currently developing the organizational framework for a potential Servicewide invasive animal program. Check back soon for a report on the state of the knowledge on invasive animals in NPS. In the meantime, discover some of the most wanted invasive animal species and learn about invasive animal management in NPS from some of the parks themselves.


"Most Wanted" Invasive Animal Species

Highlighted invasive species of concern

Some invasive animals can completely reorganize an ecosystem and provide park staff with a constant challenge to manage properly under the new circumstances.

Burmese python wrapped around an alligator
Burmese pythons and alligators have been documented to compete with each other for the role of apex predator in the ecosystem.

NPS Photo.

Burmese python

Burmese pythons, one of the largest snake species on earth, are now known to be breeding and spreading throughout south Florida. Originally from southeast Asia, more than 2,000 pythons have been removed from the park and surrounding areas since 2002, likely representing only a fraction of the total population. Like many invasive animal species, they have been introduced into the ecosystem by illegal release of unwanted pet pythons.

The Burmese python has been documented to be a voracious predator in Everglades National Park, consuming everything from raccoons to deer - and even alligators.

Close up image of a Burmese python snake
Swamp-like conditions, such as Everglades National Park, have provided the perfect habitat for Burmese pythons.

U.S. Geological Services Photo.

A mound of red fire ants clustered together
Red fire ants caught in a flood in Congaree National Park. Fire ants have interesting strategies for surviving floods, pictured. Their adaptability makes them not only a non-native species, but a highly invasive one.

NPS Photo.

Red Imported Fire Ants

The imported fire ants are very aggressive, and have been known to repeatedly attack animals that intrude on their nests. They are known to attack people, plants, and animals; they also cause damage to homes, buildings, air-conditioning units, and telephone wires.

Originally from South America, they disturb native ants, other insects, birds, and some mammals. The sting of a fire ant develops into a pustule (small, firm blister-like sore) in 24-48 hours. These pustules can become sites of secondary infection. Fire ant venom may cause a severe reaction in hypersensitive individuals; including nausea, shock, chest pains, and in rare cases, coma.

A feral swine caught in a trap by a park ranger
Feral swine caught in a trap to be removed by a park ranger.

NPS Photo.

Feral Swine

Feral swine or hogs compete directly with many native animals for food and destroy habitat for many wildlife species. They can pose threats to humans, pets, and domestic livestock through the spread of disease, such as swine brucellosis, pseudo rabies, and trichinosis.

Feral swine root and wallow in the ground searching for food, causing soil erosion, which in turn affects water quality. They destroy sensitive natural areas within national parks.

Feral swine in a forest clearing
Feral swine are descendants of escaped food animals, the Eurasian wild boar, brought over by settlers from Europe.

NPS Photo.


Invasive Animal Management in National Parks

Prevention and early detection are key to effective management of invasive animal species. The longer an invasive species survives, the more expensive and more unlikely it is for parks to successfully remove that species.

Staff at all levels of the NPS work to manage invasive animals. Park and regional staff implement strategies locally to deal with invasive animals. Although there is some overlap, the Biological Resources Division generally addresses terrestrial invasive plant and animals, while the Water Resources Division addresses not aquatic invasive species at the national level.

Contact either the Biological Resources Division or the Water Resources Division for questions on invasive animal species in national parks.

Learn more about invasive species management in parks under What We Do

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    Last updated: November 7, 2018