Bothrops alternatus
Silhouette: Steven Traver · PhyloPic
In 3 days ~50% in a week ~80%
Bothrops alternatus, known by the common names crossed pit viper, yarará grande, and urutu, among others, is a highly venomous pit viper species found in South America (Brazil, Paraguay, Uruguay and Argentina). Within its range, it is an important cause of a snakebite. The specific name, alternatus, which is Latin for "alternating", is apparently a reference to the staggered markings along its body. No subspecies are currently recognized.
Large and stout, B. alternatus reportedly exceeds 2 m (6.6 ft) in total length, although the verified maximum is 1.69 m (5.5 ft). Most specimens are 0.8–1.2 m (2.6–3.9 ft) in total length, with females being significantly longer and heavier than males.
Scalation includes 25-35 (usually 27-31/29-33 in males/females) rows of dorsal scales at midbody, 155-183/164-190 ventral scales in males/females, and 38-53/30-44 subcaudal scales in males/females. On the head are 8-13 strongly keeled intersupraocular scales, 8-10 supralabial scales, none of which is fused with the prelacunal, and 12-14 sublabial scales.
The color pattern is exceedingly variable. The ground color may be brown, tan, or gray, sometimes... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Emas National Park | 🇧🇷 Brazil | |
| 2 | El Palmar National Park | 🇦🇷 Argentina | |
| 3 | Iberá National Park | 🇦🇷 Argentina |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Buenos Aires | 🇦🇷 Argentina |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | São Paulo Zoo | 🇧🇷 Brazil | |
| 2 | Municipal Zoological Park Quinzinho de Barros | 🇧🇷 Brazil | |
| 3 | Parque Ecológico de São Carlos | 🇧🇷 Brazil | |
| 4 | Gladys Porter Zoo | 🇺🇸 United States | |
| 5 | Chattanooga Zoo at Warner Park | 🇺🇸 United States |
No species of the same family or order lives in Iberá National Park, so these are its closest relatives here: other reptiles.
Possible
About 20% of wildlife watchers report an Urutu Lancehead sighting in Iberá National Park on a given day, based on 13 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 5th most-seen of the 10 reptiles we can rate there. Over three days the chance rises to about 50%, and over a week to about 80%, if each day is a fresh chance.
January–February and July
In those months about 30% of wildlife watchers report an Urutu Lancehead in Iberá National Park on a given day, against under 5% in April, June, September and December, the lowest months.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Urutu Lancehead sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
3rd of 3
Of the 3 parks where we can rate Urutu Lancehead sightings, Iberá National Park ranks 3rd at about 20%. The best odds are in Emas National Park (Brazil, about 40%) and El Palmar National Park (Argentina, about 30%).
GBIF citizen-science records
It is estimated from how often the Urutu Lancehead is recorded against all the reptiles logged in Iberá National Park (13 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.
