Eunectes notaeus
Silhouette: Gamma 124 · PhyloPic
In 3 days ~70% in a week ~90%
The yellow anaconda (Eunectes notaeus), also known as the Paraguayan anaconda, is a boa species endemic to southern South America. It is one of the largest snakes in the world but smaller than its close relative, the green anaconda. No subspecies are currently recognized. Like all boas and pythons, it is non-venomous and kills its prey by constriction.
The Neo-Latin specific name notaeus derives from Ancient Greek: νωταίος, romanized: nōtaios, lit. 'dorsal' (νωταίος is a poetic form of νωτιαίος/nōtiaios). In distinguishing his new species Eunectes notaeus from Eunectes murinus, Edward Drinker Cope stated, "Dorsal scales are larger and in fewer rows."
Adults grow to an average of 3.7 m (12 ft 1+1⁄2 in) in total length. Females are generally larger than males and have been reported up to 4.6 m (15 ft 1 in) in length. They commonly weigh 25 to 35 kg (55 to 77 lb), but specimens weighing more than 55 kg (121 lb) have been observed. The color pattern consists of a yellow, golden-tan or greenish-yellow ground color overlaid with a series of black or dark brown saddles, blotches, spots and streaks.
The range of the yellow anaconda... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Parque Estadual Encontro das Águas | 🇧🇷 Brazil | |
| 2 | Iberá National Park | 🇦🇷 Argentina |
No species of the same family or order lives in Iberá National Park, so these are its closest relatives here: other reptiles.
Possible
About 30% of wildlife watchers report a Yellow Anaconda sighting in Iberá National Park on a given day, based on 42 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 4th most-seen of the 10 reptiles we can rate there. Over three days the chance rises to about 70%, and over a week to about 90%, if each day is a fresh chance.
July
In that month about 60% of wildlife watchers report a Yellow Anaconda in Iberá National Park on a given day, against under 5% in April and October, the lowest months. That is one of Iberá National Park's driest months, with about 70 mm of rain against 180 mm in October.
Between 2 and 5 pm
Across all the parks we cover, that three-hour window holds the most Yellow Anaconda sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
2nd of 2
Of the 2 parks where we can rate Yellow Anaconda sightings, Iberá National Park ranks 2nd at about 30%. The best odds are in Parque Estadual Encontro das Águas (Brazil, about 60%).
GBIF citizen-science records
It is estimated from how often the Yellow Anaconda is recorded against all the reptiles logged in Iberá National Park (42 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
