Lachesis muta
Silhouette: Steven Traver · PhyloPic
In 3 days ~20% in a week ~50%
Lachesis muta, also known as the Southern American bushmaster or Atlantic bushmaster, is a pit viper species found in South America, as well as the island of Trinidad in the Caribbean. Two subspecies are currently recognized, including the nominate subspecies described here.
However, both were elevated to species level by Zamudio and Green in 1997 (see L. melanocephala and L. stenophrys). Adults grow to an average of 2 to 2.5 m (6½-8 feet), although 3 m (10 feet) is not too unusual. The largest recorded specimen was 3.65 m (12 feet) long, making the species the longest of all vipers and the longest venomous snake in the Western Hemisphere. Lachesis muta is the third longest venomous snake in the world, exceeded in length only by the king cobra and the black mamba. Weight in this species is estimated at an average of 3 to 5 kg (6.6 to 11.0 lb), somewhat less than the heaviest rattlesnakes (like the eastern diamondback rattlesnake) or Bitis vipers (such as the Gaboon viper and rhinoceros viper).
The head is broad and distinct from the narrow... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Tambopata National Reserve | 🇵🇪 Peru | |
| 2 | Manu National Park | 🇵🇪 Peru |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Zoo Pilsen | 🇨🇿 Czechia | |
| 2 | Nashville Zoo at Grassmere | 🇺🇸 United States | |
| 3 | Toledo Zoo | 🇺🇸 United States | |
| 4 | Jacksonville Zoo and Gardens | 🇺🇸 United States | |
| 5 | Moody Gardens | 🇺🇸 United States | |
| 6 | Riverbanks Zoo | 🇺🇸 United States | |
| 7 | Amaru | 🇪🇨 Ecuador | |
| 8 | Agroflori Parque de las Aves | 🇧🇴 Bolivia | |
| 9 | Tennessee Aquarium | 🇺🇸 United States | |
| 10 | Underground aquarium at Jardim da Luz | 🇧🇷 Brazil |
With luck
About 10% of wildlife watchers report an Atlantic Forest Bushmaster sighting in Manu National Park on a given day, based on 11 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 48th most-seen of the 56 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.
November
In that month about 20% of wildlife watchers report an Atlantic Forest Bushmaster in Manu National Park on a given day, against under 5% in February–April, July–September and December, the lowest months. That is one of Manu National Park's wettest months, with about 240 mm of rain against 60 mm in August.
Between 8 and 11 pm
Across all the parks we cover, that three-hour window holds the most Atlantic Forest Bushmaster sightings with a recorded time, and about 6 in 10 of them come between 6 pm and 6 am: it is seen both by day and at night.
2nd of 2
Of the 2 parks where we can rate Atlantic Forest Bushmaster sightings, Manu National Park ranks 2nd at about 10%. The best odds are in Tambopata National Reserve (Peru, about 20%).
Same family: Viperidae
The closest relatives of the Atlantic Forest Bushmaster that you can see in Manu National Park (family Viperidae, Vipers) are Barba Amarilla (about 30%), Green Jararaca (about 10%) and Brazil's Lancehead (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Atlantic Forest Bushmaster is recorded against all the reptiles logged in Manu National Park (11 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.
