Desert nightsnake (Hypsiglena chlorophaea)
The desert nightsnake is a snake in the family Colubridae with a mild venom for its prey, not dangerous to people. GBIF holds 395 licensed U.S. records of it; it reaches our listing threshold in 7 states, most of all Arizona (113), California (112) and Nevada (102). Its observation records peak in May.
Hypsiglena chlorophaea, commonly known as the desert nightsnake, is a species of rear-fanged colubrid snake native to North America. It is found throughout regions of Mexico, the United States, and in a small, isolated population in British Columbia, Canada. Known for its highly secretive, nocturnal nature, it is a mildly venomous species that poses no danger to humans.
From Wikipedia: Hypsiglena chlorophaea, text under CC BY-SA 4.0.
Is the desert nightsnake poisonous or venomous?
Mildly venomous but not dangerous: the desert nightsnake has enlarged rear teeth and a mild venom for its prey, and a bite causes at most local swelling, which is why many sources simply call it harmless. It is not a pit viper or coral snake, the only U.S. land snakes with medically dangerous venom. Clean any bite like a small wound.
Which states have the desert nightsnake?
Records are spread over 7 states; the top three, Arizona, California and Nevada, hold 83% of them.
The count includes 124 records filed under the older name Hypsiglena torquata in Idaho (3), Nevada (82), Oregon (9), Utah (27) and Washington (3).
| # | State | Records | Share of state snakes | Rank in state |
|---|---|---|---|---|
| 1 | Arizona | 113 | 0.5% | 38th of 60 |
| 2 | California | 112 | 0.2% | 37th of 46 |
| 3 | Nevada | 102 | 2.5% | 14th of 27 |
| 4 | Utah | 50 | 1.5% | 8th of 28 |
| 5 | Oregon | 10 | 0.1% | 14th of 16 |
| 6 | Idaho | 5 | 0.3% | 10th of 11 |
| 7 | Washington | 3 | 0.1% | 11th of 11 |
When is the desert nightsnake seen?
Across the U.S., observation records of the desert nightsnake run mostly March through September, peaking in May with 21% of them. Winter (December to February) holds 5% of them.
Where the desert nightsnake is recorded in each state
Arizona
Arizona holds 113 licensed records, the 38th most recorded of 60 snakes listed there. Its observation records in Arizona run mostly April through November, peaking in August; most licensed records come from Pima County, Maricopa County and Santa Cruz County. Next come Coconino County (8) and Yavapai County (6).
California
California holds 112 licensed records, the 37th most recorded of 46 snakes listed there. Most of its licensed records in California come from San Diego County, Inyo County and Riverside County. Next come San Bernardino County (11) and Imperial County (6).
Nevada
Nevada holds 102 licensed records, the 14th most recorded of 27 snakes listed there. Most of its licensed records in Nevada come from Clark County, Nye County and White Pine County. Next come Lincoln County (2) and Esmeralda County (1).
Utah
Utah holds 50 licensed records, the 8th most recorded of 28 snakes listed there. Most of its licensed records in Utah come from Utah County, Tooele County and Garfield County. Next come Kane County (5) and Salt Lake County (5).
Top counties in the U.S.
| # | County | State | Records | Share of U.S. |
|---|---|---|---|---|
| 1 | Clark County | Nevada | 62 | 15.7% |
| 2 | San Diego County | California | 56 | 14.2% |
| 3 | Pima County | Arizona | 53 | 13.4% |
| 4 | Nye County | Nevada | 32 | 8.1% |
| 5 | Maricopa County | Arizona | 21 | 5.3% |
| 6 | Inyo County | California | 13 | 3.3% |
| 7 | Riverside County | California | 12 | 3.0% |
| 8 | San Bernardino County | California | 11 | 2.8% |
| 9 | Santa Cruz County | Arizona | 10 | 2.5% |
| 10 | Utah County | Utah | 9 | 2.3% |
| 11 | Coconino County | Arizona | 8 | 2.0% |
| 12 | Tooele County | Utah | 7 | 1.8% |
| 13 | Garfield County | Utah | 7 | 1.8% |
| 14 | Yavapai County | Arizona | 6 | 1.5% |
| 15 | Imperial County | California | 6 | 1.5% |
How recent are the desert nightsnake records?
The desert nightsnake record leans on older material: only 23% of dated U.S. records come from 2017–2026, and the median record is from 1975. The oldest dated record is from 1891; the busiest year was 1966, with 32 records.
| Decade | Records | Share |
|---|---|---|
| 1890s | 1 | 0.3% |
| 1900s | 2 | 0.5% |
| 1910s | 3 | 0.8% |
| 1920s | 6 | 1.5% |
| 1930s | 33 | 8.5% |
| 1940s | 36 | 9.3% |
| 1950s | 27 | 7.0% |
| 1960s | 60 | 15.5% |
| 1970s | 41 | 10.6% |
| 1980s | 5 | 1.3% |
| 1990s | 14 | 3.6% |
| 2000s | 45 | 11.6% |
| 2010s | 43 | 11.1% |
| 2020s | 72 | 18.6% |
Species recorded in the same counties
Of the 43 counties where the desert nightsnake is most recorded, 40 are also top counties for the gopher snake, more than for any other snake. Venomous species among its neighbors: the western rattlesnake.
| Species | Shared counties |
|---|---|
| Gopher snake | 40 |
| Striped whipsnake | 32 |
| California kingsnake | 30 |
| Western rattlesnake venomous | 29 |
| Western terrestrial garter snake | 26 |
| Coachwhip | 24 |
| Long-nosed snake | 23 |
| Western patch-nosed snake | 23 |
Related species in the U.S.
Other members of the family Colubridae with profiles here: Western terrestrial garter snake, Common garter snake, Gopher snake, Ring-necked snake, Northern water snake and Eastern racer.
GBIF records read 2026-09-29. Listed: any license. Counted: CC0/CC BY only. How we count.