March 20, 2014

Everglades National Park, in the Florida Everglades, has a major problem with invasive species, including the giant Burmese python (National Park Service).

Giant Burmese pythons have a magnetic sense that directs them “home” over vast distances, scientists announced yesterday in the Royal Society journal Biology Letters. To study how these invasive predators migrate and spread, scientists captured and relocated 12 pythons in Florida’s Everglades National Park. The huge snakes were fitted with GPS radio transmitters. Half were released where they were captured; the other half was transported to other areas in the park—13 to 23 miles (21 to 36 kilometers) from where they were captured. Using aircraft to track their movements, the scientists were amazed to discover that 5 of the 6 pythons quickly returned to within 3 miles (5 kilometers) of the place where they had been captured. “We were very surprised,” noted the study’s lead author Shannon Pittman of Davidson College in North Carolina. “We anticipated the pythons would develop new home ranges where they were released. We didn’t expect them to orient back to their capture locations.” Pittman stated that the experiment provided the first evidence that snakes may share a similar magnetic sense as other reptiles, such as sea turtles. Dr. Pittman suggested that staying in familiar territory may help snakes find prey and mates, and this homing sense may allow them to return to their territory after exploratory forays. “We know that snakes tend to come back to some of the same sites throughout their lives such as overwintering locations or refuges.”

The Burmese python, a native of Southeast Asia, has become established in the Everglades as a result of people dumping unwanted pet pythons. One of the largest snakes in the world, the python has been measured at more than 15 feet (4.5 meters) and weighing in excess of 160 pounds (72.5 kilograms). The snakes coil around a prey animal and suffocate it. Pythons have been known to kill and swallow adult alligators and have been blamed for a staggering decline in the numbers of native mammals in the Everglades. Conservation surveys conducted between 2003 and 2011 documented a 9.3-percent decrease in the frequency of raccoon observations and decreases of 98.9 percent and 87.5 percent in opossum and bobcat observations, respectively. No native marsh rabbits were detected during the entire length of the survey. Understanding how invasive pythons migrate could help control their spread in Florida, Pittman told BBC news.

Additional World Book articles:

• Invasive Species (a special report)
• New Top Predator? Pythons in the Everglades

August 17, 2012

The recent discovery of the biggest Burmese python ever found in Florida is convincing evidence of just how well established these highly destructive reptiles have become in Everglades National Park and other parts of South Florida, according to Florida scientists. The snake was 17 feet 7 inches (5.35 meters) long and weighed 164 1/2 pounds (76 kilograms). Scientists recovered 87 eggs from the snake–also  a record for the state. The pythons “are surviving a long time in the wild,” said snake expert Kenneth Krysko of the Florida Museum of Natural History. “There’s nothing stopping them.” About 1,825 Burmese pythons were discovered in Everglades National Park from 2000 to 2011. However, scientists think the python population is many times higher.

Native to Southeast Asia, the python is classified as an invasive species in North America. From 1999 to 2004, pet exporters met a growing American demand for Burmese pythons by shipping more than 144,000 baby snakes to the United States. However, new owners were frequently unprepared or unwilling to care for the massive snakes in adulthood. Many owners dumped their snakes into the wild. Pythons released into the Everglades, a region with a climate similar to that of the snakes’ native habitat, flourished. Pythons also have escaped into the wild during hurricanes.

Young Indian pythons hatch from eggs outside the mother's body. The leathery shells of snake eggs expand as the young snakes grow inside. When they are ready to hatch, young snakes slash their shells with a special tooth that grows on the upper jaw. (AP/Wide World)

The pythons have devastated the mammal population of the Everglades and were targeting the park’s birds, according to a study released in April 2012. The study was the first to provide evidence linking a sharp decline in populations of medium- and large-sized mammals in the park to an explosion in the number and range of the large snakes. The record-holding snake found recently had feathers in its stomach.

Wildlife experts agree that eliminating the secretive and hard-to-hunt snakes from the park would be impossible. They are unsure if the spread of the snakes, which have no natural predators in North America, can be halted. In January, the administration of President Barack Obama outlawed the import and interstate commerce of Burmese pythons, two other pythons, and the yellow anaconda. Reptile importers are still allowed to trade in reticulated pythons and boa constrictors. Florida permits residents to hunt pythons under certain conditions.

Additional World Book articles:

• Ecology
• Invasive Species (A Special Report)
• Reptile

April 9, 2012

After devastating the mammal population of Everglades National Park in Florida, Burmese pythons are targeting the park’s birds. They are not only eating area birds but also taking their eggs straight from the nest.

Researchers from the Smithsonian Museum of Natural History have monitored the invasive snake’s diet by examining the stomach contents of captured pythons. They found that the diets of some 300 captured snakes consisted of more than 25 species of birds. They also found eggs inside the snakes, proof that they are attacking nests. Most snakes that eat eggs puncture the shells with fangs and suck out the contents. However, the researchers found shell fragments inside the snakes, suggesting that they eat the eggs whole. “This finding is significant because it suggests that the Burmese python is not simply a sit-and-wait predator, but rather is opportunistic enough to find the nests of birds,” noted Carla Dove, a researcher with the Smithsonian study. “Although the sample size is small, these findings suggest that the snakes have the potential to negatively affect the breeding success of native birds.” The study was reported in the March 2012 issue of the journal Reptiles & Amphibians: Conservation and Natural History.

An earlier study, published in March 2012 by two Florida university researchers, revealed that pythons were battling alligators for the position of top predator in the Everglades. That study was the first to provide evidence linking a sharp decline in populations of medium- and large-sized mammals in the park to an explosion in the number and range of the large snakes.

Egrets are among the most beautiful birds in the Everglades. (World Book illustration by Trevor Boyer, Linden Artists Ltd.)

Native to Southeast Asia, the Burmese python is classified as an invasive species in North America. From 1999 to 2004, pet exporters met a growing American demand for Burmese pythons by shipping more than 144,000 baby snakes to the United States. However, new owners were frequently unprepared or unwilling to care for the grown snakes, which can measure 23 feet (7 meters) in length and weigh 200 pounds (91 kilograms). Many owners dumped their snakes into the wild. Pythons released into the Florida Everglades, a region with a climate similar to that of the snakes’ native habitat, flourished. Pythons also have escaped into the wild during hurricanes.

Researchers surveyed native mammal populations over 313 nights during an eight-year period by counting live and dead animals along a road that runs to the southern tip of the park. They then compared their tallies to population surveys done in 1996 and 1997. In areas of the Everglades where pythons have lived the longest, populations of raccoons had fallen by 99.3 percent. The number of opossums had dropped by 98.9 percent, and bobcat populations had fallen by 88.5 percent. The researchers were unable to find any rabbits or foxes. Populations of native animals were larger in areas more recently or not yet invaded by the snakes.

The U.S. Association of Reptile Keepers disputed the findings of the study. The organization contended that mercury pollution in the Everglades has played a major role in the disappearance of the mammals.

Young Indian pythons hatch from eggs outside the mother's body. (AP/Wide World)

Wildlife experts agree that eliminating the secretive and hard-to-hunt snakes from the park would be impossible. They are unsure if the spread of the snakes, which have no natural predators in North America, can be halted. In January, the federal government outlawed the import and interstate commerce of Burmese pythons, two other pythons, and the yellow anaconda. Reptile importers are still allowed to trade in reticulated pythons and boa constrictors.

Additional World Book articles:

• Ecology
• Invasive Species (A Special Report)
• Reptile

Feb. 6, 2012

Pythons are battling alligators for the position of top predator in Everglades National Park in Florida, and native mammals are paying the price, according to a new study by two Florida university researchers. The study is the first to provide evidence linking a sharp decline in populations of medium- and large-sized mammals in the park to an explosion in the number and range of the large snakes.

Native to Southeast Asia, the python is classified as an invasive species in North America. From 1999 to 2004, pet exporters met a growing American demand for Burmese pythons by shipping more than 144,000 baby snakes to the United States. However, new owners were frequently unprepared or unwilling to care for the grown snakes, which can measure 23 feet (7 meters) in length and weigh 200 pounds (91 kilograms). Many owners dumped their snakes into the wild. Pythons released into the Florida Everglades, a region with a climate similar to that of the snakes’ native habitat, flourished. Pythons also have escaped into the wild during hurricanes.

The study’s researchers surveyed native mammal populations over 313 nights during an eight-year period by counting live and dead animals along a road that runs to the southern tip of the park. They then compared their tallies to population surveys done in 1996 and 1997. In areas of the Everglades where pythons have lived the longest, populations of raccoons had fallen by 99.3 percent. The number of opossums had dropped by 98.9 percent, and bobcat populations had fallen by 88.5 percent. The researchers were unable to find any rabbits or foxes. Populations of native animals were larger in areas more recently or not yet invaded by the snakes.

The U.S. Association of Reptile Keepers disputed the findings of the study. The organization contended that mercury pollution in the Everglades has played a major role in the disappearance of the mammals.

Young Indian pythons hatch from eggs outside the mother's body. The leathery shells of snake eggs expand as the young snakes grow inside. When they are ready to hatch, young snakes slash their shells with a special tooth that grows on the upper jaw. AP/Wide World

Wildlife experts agree that eliminating the secretive and hard-to-hunt snakes from the park would be impossible. They are unsure if the spread of the snakes, which have no natural predators in North America, can be halted. In January, the administration of President Barack Obama outlawed the import and interstate commerce of Burmese pythons, two other pythons, and the yellow anaconda. Reptile importers are still allowed to trade in reticulated pythons and boa constrictors.

Additional World Book articles:

• Ecology
• Invasive Species (A Special Report)
• Reptile