Bothrops alternatus
Silhouette: Steven Traver · PhyloPic
In 3 days ~80% in a week >90%
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 |
Likely
About 40% of wildlife watchers report an Urutu Lancehead sighting in Emas National Park on a given day, based on 20 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 5th most-seen of the 11 reptiles we can rate there. Over three days the chance rises to about 80%, and over a week to over 90%, if each day is a fresh chance.
June
In that month about 70% of wildlife watchers report an Urutu Lancehead in Emas National Park on a given day, against under 5% in July–August and November–December, the lowest months. That is one of Emas National Park's driest months, with about 10 mm of rain against 190 mm in January.
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.
Yes
Of the 3 parks where we can rate Urutu Lancehead sightings, Emas National Park has the highest daily chance: about 40%. Next come El Palmar National Park (Argentina, about 30%) and Iberá National Park (Argentina, about 20%).
Same genus: Bothrops
The closest relatives of the Urutu Lancehead that you can see in Emas National Park (genus Bothrops, Neotropical Lanceheads) are Cerrado Lancehead (about 50%) and Brazilian Lancehead (about 30%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Urutu Lancehead is recorded against all the reptiles logged in Emas National Park (20 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.
