The Amazon’s Largest Predator: A New Species of Giant Anaconda Discovered

The largest snake known to inhabit the Amazon is the green anaconda. It is considered the largest snake in the world by weight. The only snake that regularly exceeds it in length is the reticulated python from Southeast Asia.

Reticulated pythons can reach lengths of around 20 feet and, in rare historical accounts, even longer. One record from Thailand in 1912 claims a python measured 32 feet, 9.5 inches. While this record is debated, reticulated pythons are generally longer than any other snake species, though they are not as heavy-bodied as anacondas.

Green anacondas belong to the boa family, Boidae, and are often referred to as water boas due to their strong association with aquatic environments.

Water provides buoyancy, helping support their massive bodies. One of their most notable adaptations is the placement of their nostrils on top of the head. This allows them to breathe while remaining mostly submerged, which is especially useful when ambushing prey along riverbanks while concealed by vegetation.

Capybara (Hydrochoerus hydrochaeris)

Green anacondas are opportunistic predators that feed on a wide range of animals, including birds, mammals, and reptiles.

A common prey item is the capybara, the world’s largest rodent, which can weigh over 100 pounds. Anacondas can also prey on caimans, the alligators of South America. Smaller caimans, in particular, are vulnerable to the powerful coils of a large anaconda.

Among large constrictors, females are significantly larger than males, and this is especially true for green anacondas. While a large male may reach around 10 feet, females can grow much larger.

During mating, multiple males may compete for a single female, forming what is known as a mating ball. It is possible for more than one male to successfully reproduce, resulting in offspring from multiple fathers.

Unlike many reptiles, anacondas give birth to live young. Newborns are already sizable, measuring close to 36 inches at birth.

Despite everything known about green anacondas, the mysteries of the Amazon continue to surprise us. In 2024, National Geographic documented an expedition led by Dr. Bryan Fry alongside Will Smith as part of the series Pole to Pole.

The team traveled deep into Ecuador’s Amazon rainforest to study anacondas and test for toxin levels caused by environmental pollution. Toxins accumulate in apex predators through a process known as bioaccumulation.

During the expedition, the team, along with members of the Waorani community, discovered exceptionally large anacondas. One specimen measured 20.7 feet and weighed 440 pounds. Local knowledge suggested that even larger individuals may exist.

Northern Green Anaconda (Eunectes akayima)

In addition to size records, the expedition led to a groundbreaking discovery. Blood samples revealed that these anacondas were genetically distinct from previously known green anacondas.

The DNA differed by 5.5%, confirming the identification of a new species: the northern green anaconda (Eunectes akayima). Scientists believe this species diverged from its southern relative around 10 million years ago.

While visually similar, the northern green anaconda is darker in color and is now believed to grow even larger than its southern counterpart.

Could even larger anacondas still exist, hidden deep within the Amazon? The discovery of a new species suggests that there are still many secrets waiting to be uncovered.

The legends of giant serpents like the Yacumama may not be entirely rooted in myth after all. As exploration continues, the possibility of encountering even larger and more mysterious creatures remains an exciting prospect.