Science July Ian Frazier; Photographs by Gena Steffens. In the Everglades, everything still looks the same. But now there is also a weird quiet. In fact, roadkill, which used to be common in this wildest part of Florida, is no longer seen.
The raccoons and marsh rabbits and opossums and other small, warmblooded animals are gone, or almost gone, because Burmese pythons seem to have eaten them. About two feet long when hatched, Burmese pythons can grow to 20 feet and pounds; they are among the largest snakes in the world. The pythons are mostly ambush hunters, and constrictors. They kill smaller animals by biting them on or near the head and suffocating them as they are swallowed. Larger animals are seized wherever is convenient, and crushed and strangled in the coils before and during swallowing.
Large constrictor snakes have not existed in North America for millions of years. Native wildlife species had never seen them before, and may not recognize them as predators. In Miami, a center of the exotic pet trade, dealers used to import them from Southeast Asia by the tens of thousands. It is now illegal to import or purchase Burmese pythons in Florida. Probably, at some point, python owners who no longer wanted to care for them let them go in the Everglades. By the mids, the pythons had established a breeding population.
For 25 years they have been eating any animals they can get their mouths around. A study found that, of a group of marsh rabbits fitted with radio transmitters and released into python territory, 77 percent of those that died within a year had been eaten by pythons. Scientists say that the snakes are responsible for a recent 90 to 99 percent drop in the small mammal population in the national park.
No one knows how many pythons are out there now. Estimates run from 10, to perhaps hundreds of thousands. Their black-brown-tan camouflage fits perfectly in the marsh, as well as in the higher sandy ground that makes up another part of their range. They are good swimmers and can stay underwater for half an hour or more. Frank Mazzotti, a scientist who has been studying them for more than a decade, told me about a time when he and his colleagues caught a python, attached a radio transmitter for research purposes, and released it.
