What If Gone

Species → Burmese Python

Burmese Python

Python bivittatus

no global census; the IUCN documents a decline of 30 to more than 50%…
Extinction risk Vulnerable
Invasive speciesApex predatorTrophic cascadeWetland
Burmese Python (Python bivittatus)
Photo: Cvmontuy, Wikimedia Commons (CC BY-SA 4.0)

What if it disappeared?

Impact High
Over 8 years (Everglades)

Where the introduced Burmese python has established itself, nighttime road surveys totaling nearly 57,000 km measured a collapse in mammal sightings: raccoons down 99.3%, opossums down 98.9%, bobcats down 87.5%, and no rabbits detected at all — while these same species remain abundant in areas still beyond the python's range.

Documented
Detail

Dorcas, M.E., Willson, J.D., Reed, R.N., Snow, R.W., Rochford, M.R., Miller, M.A., Meshaka, W.E. Jr., Andreadis, P.T., Mazzotti, F.J., Romagosa, C.M. & Hart, K.M. (2012). Severe mammal declines coincide with proliferation of invasive Burmese pythons in Everglades National Park. Proceedings of the National Academy of Sciences, 109(7), 2418-2422.

The study compares mammal sighting rates along park roads before and after python establishment, and across long-invaded, recently invaded, and still python-free zones. The geographic and temporal gradient is clear: the longer pythons have been present, the more severe the mammal decline — which rules out a climatic or seasonal cause common to the whole park.

In the following years, Florida

The collapse of raccoons and opossums — two nest predators — measurably reduced sea turtle nest predation on beaches where the python has become established: an indirect cascading effect, since the python never preys on nests itself.

Documented
Detail

Willson, J.D. (2017). Indirect effects of invasive Burmese pythons on ecosystems in southern Florida. Journal of Applied Ecology, 54(4), 1251-1258.

The synthesis compares nest predation rates (scored on a 1-5 scale) across sites by invasion history: an average score of 1.5 where the python is long established, versus 4.6 where it is absent or recently arrived. The effect operates entirely through the suppression of nest-predating mammals, not through any direct action by the python.

Open question

Florida has funded python removal campaigns for years, but no study has been able to measure whether sufficient removal would bring raccoon, opossum, and rabbit populations back to their pre-invasion levels, or whether other changes since then make such recovery unlikely.

Insufficient
Detail

Annual captures, even in the hundreds during publicized contests like the "Python Challenge," remain tiny against an invasive population estimated in the tens of thousands spread across hard-to-access terrain. No site has yet achieved removal sufficient to test whether the cascade is reversible.

Documentation

Last verified: August 14, 2026