![]() Some species retain a pelvic girdle with a pair of vestigial claws on either side of the cloaca. To accommodate their narrow bodies, snakes' paired organs (such as kidneys) appear one in front of the other instead of side by side, and most have only one functional lung. Many species of snakes have skulls with several more joints than their lizard ancestors, enabling them to swallow prey much larger than their heads ( cranial kinesis). Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes / s ɜːr ˈ p ɛ n t iː z/. Buck, E.Approximate world distribution of snakes, all species Government Printing Office, September 1993). Office of Technology Assessment, Harmful Non-Indigenous Species in the United States, The costs of brown tree snake detection and control are estimated at $2.5 million per year. Dog teams are being used currently in Honolulu for snake detection. Controls for the brown tree snake include fumigation of cargo with methyl bromide as well as the use of toxicants, baits, and traps. The 1990 Nonindigenous Aquatic Nuisance Prevention and Control Act directed that a program be developed to control the snake in Guam. In 1992, the Department of Defense was granted $1 million in new money for brown tree snake research and control. For this reason, the United States has become engaged in the struggle to control and eradicate the brown tree snake. If one pregnant snake escaped into the brush, however, it could damage the natural fauna of Hawaii as well as its tourist industry. Brown tree snakes have been intercepted six times at the Honolulu airport but the island has been spared colonization as of yet. The brown tree snake is able to live for long periods of time without food, allowing the snake to survive in cargo holds of ships or planes. The brown tree snake also crawls along electrical lines, causing approximately one power outage every four days, which results in a cost of over $1 million annually. Approximately 200 people have been treated for snakebites, as the snake often enters houses through air ducts or sewage lines. The brown tree snake has taken its toll on the human population, as well. Its predation of native birds has been so complete that the brown tree snake is now sustained almost entirely by feeding on the introduced lizard species of the island. Preying on eggs and birds alike, the snake has eliminated 9 of the 11 native land bird species in Guam and many of the non-native species. ![]() The indigenous birds of Guam evolved in a snake-free habitat and consequently lack the protective behavior or barriers of other birds, making them easy prey for the brown tree snake. The brown tree snake feeds on rats, shrews, and lizards, but prefers birds. It has now reached densities of up to 30,000 per square mile. ![]() Aggressive and venomous, the brown tree snake has no natural predators on Guam and soon established itself throughout the entire island. The brown tree snake, which is native to Papua New Guinea, was accidentally introduced to Guam in the 1940s through U.S. The brown tree snake Boiga irregularis provides a startling example of the negative effects invasive species can have on indigenous fauna. You are in: Under Secretary for Democracy and Global Affairs > Oceans and International Environmental and Scientific Affairs > Oceans > Invasive Species > Case Studies Case Study: Brown Tree Snake ![]()
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