Hypsiglena jani
Silhouette: Jose Carlos Arenas-Monroy · PhyloPic
In 3 days ~50% in a week ~80%
Hypsiglena jani, commonly known as the Texas night snake or the Chihuahuan night snake, is a small species of mildly venomous snake in the subfamily Dipsadinae of the family Colubridae. The species is native to the southwestern United States and adjacent northeastern Mexico.
The epithet, jani, is in honor of Italian taxonomist Giorgio Jan. H. jani grows from 10 to 16 inches (25 to 41 centimetres) in total length (including tail), record 20 inches (51 cm). It is typically a light gray or tan in color, with dark brown or dark gray blotching down the back, and has an unmarked underside. It has smooth dorsal scales. The eye has a vertically elliptical pupil. H. jani is rear-fanged, and is considered to be venomous, though it is not dangerous to humans.
As the common names imply, H. jani is a primarily nocturnal snake. The diet of H. jani consists of primarily lizards, but it will also eat smaller snakes and occasionally soft bodied insects. H. jani prefers semi-arid habitats with rocky soils.
H. jani is an oviparous species that breeds in the spring rainy season, laying 4–6 eggs that take approximately... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Big Bend National Park | 🇺🇸 United States |
More parks will be added in future updates.
Possible
About 20% of wildlife watchers report a Chihuahuan Nightsnake sighting in Big Bend National Park on a given day, based on 52 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 19th most-seen of the 48 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.
September
In that month about 40% of wildlife watchers report a Chihuahuan Nightsnake in Big Bend National Park on a given day, against under 5% in February and November–December, the lowest months. That is one of Big Bend National Park's wettest months, with about 50 mm of rain against 10 mm in April.
Between 9 pm and midnight
Across all the parks we cover, that three-hour window holds the most Chihuahuan Nightsnake sightings with a recorded time, and about 8 in 10 of them come between 6 pm and 6 am: it is mostly seen at night.
Only Big Bend National Park, in our data
Big Bend National Park is the only park on Wallace's Line with enough records to rate Chihuahuan Nightsnake sightings: about 20% of wildlife watchers there report one on a given day.
Same family: Colubridae
The closest relatives of the Chihuahuan Nightsnake that you can see in Big Bend National Park (family Colubridae, Colubrid Snakes) are Trans-pecos Ratsnake (about 30%), Coachwhip (about 20%) and Long-nosed Snake (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Chihuahuan Nightsnake is recorded against all the reptiles logged in Big Bend National Park (52 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.
