Chironius bicarinatus
Silhouette: Alex Slavenko · PhyloPic
In 3 days ~20% in a week ~40%
Chironius bicarinatus, the two-headed sipo, is a species of snake in the family Colubridae. The species is found in Brazil, Argentina, Uruguay, and Paraguay. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Tijuca National Park | 🇧🇷 Brazil |
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Rio de Janeiro | 🇧🇷 Brazil | |
| 2 | São Paulo | 🇧🇷 Brazil |
With luck
About 10% of wildlife watchers report a Two-headed Sipo sighting in Tijuca National Park on a given day, based on 9 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 13th most-seen of the 21 reptiles we can rate there. Over three days the chance rises to about 20%, and over a week to about 40%, if each day is a fresh chance.
March, June, August, October and December–January
In those months about 10% of wildlife watchers report a Two-headed Sipo in Tijuca National Park on a given day, against under 5% in February, April–May, July, September and November, the lowest months.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Two-headed Sipo sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Only Tijuca National Park, in our data
Tijuca National Park is the only park on Wallace's Line with enough records to rate Two-headed Sipo sightings: about 10% of wildlife watchers there report one on a given day.
Same genus: Chironius
The closest relatives of the Two-headed Sipo that you can see in Tijuca National Park (genus Chironius, Sipos) are Brown Sipo (about 10%) and Coastal Sipo (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Two-headed Sipo is recorded against all the reptiles logged in Tijuca National Park (9 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.
