The Burmese python is a notorious invasive species wreaking havoc on the Florida Everglades. With lengths exceeding 19 ft and weights over 125 lb, these snakes rank among the largest in the world.

The record‑length specimen—caught by two hunters in Florida's Big Cypress National Preserve in 2023—measured 19 ft (5.8 m) and weighed 125 lb (57 kg). The heaviest documented—captured by wildlife biologists at the Conservancy of Southwest Florida in 2022—reached 18 ft (5.5 m) and tipped the scales at 215 lb (98 kg). Compared with the world‑record green anaconda, Burmese pythons still fall short in both dimensions.

While filming National Geographic’s “Pole to Pole” series in 2024, researchers in Ecuador’s Amazon discovered the largest green anaconda on record: 26 ft (7.9 m) long and 440 lb (200 kg) heavy. That figure is 7 ft longer and more than twice the mass of the largest Burmese python caught to date, and it is also the heaviest snake documented worldwide.

Guinness World Records cites an unconfirmed specimen from Brazil (circa 1960) that measured 27.7 ft (8.4 m) and was estimated to weigh between 500 and 880 lb (227–399 kg) thanks to its 3.6‑ft girth. The Waorani of Ecuador report that anacondas can reach 30 ft (9.1 m) and exceed 1,100 lb (500 kg). On average, females range from 9.8 to 16.3 ft (3 to 5 m) with a 1‑ft girth and commonly weigh over 550 lb (250 kg).

Green anacondas (Eunectes murinus) dominate the tropical rainforest food web, spending most of their lives in sluggish rivers, marshes, and swamps. Though not venomous, their immense muscular bodies make them formidable predators: they constrict fish, turtles, deer, jaguars, and other mammals, and can survive weeks or even months without feeding.

In 2024, scientists published a paper in MDPI Diversity revealing that what was once considered a single species actually comprises two distinct lineages. The southern green anaconda (Eunectes murinus) and the newly identified northern green anaconda (Eunectes akayima) differ by 5.5 % in their DNA, a genetic gap larger than that between chimpanzees and humans. The discovery, made during the same “Pole to Pole” expedition, highlights the genetic diversity of these iconic reptiles.

Understanding the true size, distribution, and biology of both Burmese pythons and green anacondas is essential for conservation efforts and for protecting the ecosystems they influence.