Bullfrogs hitchhiked globally on dinner plates
Lithobates catesbeianus, the American bullfrog, is eastern North America's giant true frog of permanent ponds and swamps. People ate it so eagerly that introductions now span more than forty countries. Outside its native range—from western U.S. states to South America and beyond—it often becomes an invasive predator of local amphibians.
Mark Catesby is honoured in the specific epithet; some authors still prefer Rana catesbeiana. Adults show olive-green backs, pale blotched bellies, and a sharp colour break between green upper and pale lower lips. Males are smaller with yellow throats and tympana larger than their eyes; females' ear discs match eye size. Snout-vent length runs about nine to fifteen centimetres. Young pack on mass quickly, climbing from roughly five to one hundred seventy-five grams in the first eight months under good conditions.
Besides food markets, bullfrogs supply school dissections; albino adults appear in the pet trade and tadpoles in pond shops. Western U.S. introductions cover Arizona through Washington and Wyoming, plus Nantucket. Self-sustaining British populations appeared around nineteen ninety-nine from escapes and releases; Natural England works to control them because they threaten native amphibians. Adult predators range from belted kingfishers to American alligators.
The same traits that make bullfrogs hardy neighbours—big appetite, tolerance of artificial pools and canals, loud carrying calls—turn problematic abroad. They outcompete or eat local reptiles and amphibians where food webs never met such a generalist. Native southern U.S. wetlands still support heavy harvest pressure; exported frogs rewrite foreign ponds. A dinner specialty became a biogeographic experiment still unfolding on multiple continents. Native range centers on eastern North America, yet the same appetite that made the frog a Southern table staple also seeded self-sustaining colonies wherever people released or escaped stock. Controlling those footholds is now a conservation chore from western reservoirs to English wetlands.
Source: American bullfrog
