In the News
Pythons squeeze
out local species
in South Florida
Some mammal populations
fall by more than 90 percent
plummeting throughout the pythons’
expanding range. And the timing of these
mammal losses matches the geographic
spread of the snakes, which federal offi-
cials believe were initially released into
the wild in Florida by snake fanciers,
probably 15 to 30 years ago.
Raccoon, opossums, deer and other
mammals, along with birds and alligators, have all turned up in the stomachs
of captured pythons, testifying to the
snakes’ varied appetite, notes ecologist
Michael Dorcas of Davidson College in
North Carolina. “But until now, there
hadn’t been any indication that the
snakes were altering the ecosystem,”
says Dorcas, who led the study.
The new data “make a persuasive case
for cause and effect,” says herpetologist
J. Whitfield Gibbons of the Savannah
River Ecology Lab in Aiken, S.C., who was
not affiliated with the new analysis. “The
investigators take a convincing position
that introduced predatory pythons are
STORY ONE
University of Florida scientists show
off a 4.5-meter Burmese python, weighing more than 72 kilograms, that was
captured in the Everglades. Its stomach contained a 2-meter-long alligator.
Giant snakes are eating their way through the Everglades, leaving a drastically changed ecosystem in their wake, a
new study shows.
The snakes, many of which measure
3 to 5 meters, are called Burmese
pythons. But make no mistake: Virtu-
ally all of the estimated 30,000 living
in southern Florida were born in the
Everglades. Ecologists now report that
populations of mammals have begun
responsible for the decline in numbers
of large- and medium-size mammals in
the Everglades.”
With much of the roughly
6,000-square-kilometer Everglades
National Park virtually inaccessible,
the team of 11 scientists took an indi-
rect approach to surveying the region’s
mammal populations. From 2003 to
2011, researchers cruised roads on 313
nights and compared the number of
individuals in each species they saw per
100 kilometers traveled with rates wit-
nessed along the same roadways over 51
nights in the 1990s — before pythons had
established local breeding populations.
www.sciencenews.org
february 25, 2012 | SCIENCE NEWS | 5
