Bothrops jararacussu
Silhouette: Steven Traver · PhyloPic
In 3 days ~20% in a week ~50%
Bothrops jararacussu, commonly known in English as the jararacussu, is a highly venomous pit viper species endemic to South America. It is one of the most dreaded snakes in South America and can grow up to 2.2 metres (7.2 ft).
The jararacussu is a fairly large pit viper, growing up to 2.2 meters long, with a robust body and head and very aggressive behavior. The color of the body and head varies widely; the background color can be brown or yellow, almost black, the pattern of dark and light scales are constituted in a series of dark arches. The spots form on the dorsal midline, which look like the letter x. It has medium-sized eyes, with elliptical pupils vertically. With dorsal scales strongly keeled.
They have large fangs of 2.5 cm, and can inject a lot of venom. They usually feed on amphibians and rodents. They are ovoviviparous, giving birth to between 16 and 20 young, in the rainy season. Mainly diurnal and nocturnal, they usually warm up in the morning sun and venture forth to hunt at night.
It is found in South America in coastal Brazil (from Bahia to Santa Catarina), Paraguay, southeastern Bolivia, and northeastern Argentina... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Serra dos Órgãos National Park | 🇧🇷 Brazil | |
| 2 | Iguazú National Park | 🇦🇷 Argentina | |
| 3 | Iguaçu National Park | 🇧🇷 Brazil | |
| 4 | Tijuca National Park | 🇧🇷 Brazil |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Rio de Janeiro | 🇧🇷 Brazil |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | São Paulo Zoo | 🇧🇷 Brazil |
With luck
About 10% of wildlife watchers report a Jararacussu sighting in Iguazú National Park on a given day, based on 7 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 13th most-seen of the 18 reptiles we can rate there. Over three days the chance rises to about 20%, and over a week to about 50%, if each day is a fresh chance.
September and November
In those months about 20% of wildlife watchers report a Jararacussu in Iguazú National Park on a given day, against under 5% in May, July–August, October and December–February, the lowest months.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Jararacussu sightings with a recorded time, and about 7 in 10 of them come between 6 am and 6 pm: it is seen both by day and at night.
2nd of 4
Of the 4 parks where we can rate Jararacussu sightings, Iguazú National Park ranks 2nd at about 10%. The best odds are in Serra dos Órgãos National Park (Brazil, about 20%).
Same genus: Bothrops
The closest relatives of the Jararacussu that you can see in Iguazú National Park (genus Bothrops, Neotropical Lanceheads) are Brazilian Lancehead (about 20%) and Painted Lancehead (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Jararacussu is recorded against all the reptiles logged in Iguazú National Park (7 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.
