Sidewinder (Crotalus cerastes)
The sidewinder is a venomous pit viper in the family Viperidae. GBIF holds 3,119 licensed U.S. records of it; it reaches our listing threshold in 4 states, most of all California (1,923), Arizona (875) and Nevada (305). Its observation records peak in April.
Crotalus cerastes, also known commonly as the horned rattlesnake, the sidewinder, and the sidewinder rattlesnake, is a species of pit viper, a venomous snake in the subfamily Crotalinae of the family Viperidae. The species is native to desert regions of the Southwestern United States and adjacent northwestern Mexico. Three subspecies are recognized as being valid.
From Wikipedia: Crotalus cerastes, text under CC BY-SA 4.0.
Is the sidewinder poisonous or venomous?
Yes. The sidewinder is a pit viper (family Viperidae), like every rattlesnake, copperhead and cottonmouth in the U.S. Its bite needs emergency care: call 911 and keep the bitten limb still. Antivenom is given in hospital.
Snakes often mistaken for it
Species commonly confused with rattlesnakes and recorded in the same states: gopher snake (recorded in all 4 of its states), Great Plains rat snake (recorded in 1 of its 4 states) and plains hog-nosed snake (recorded in 1 of its 4 states).
Which states have the sidewinder?
The sidewinder's U.S. record is concentrated: California alone holds 62% of licensed records. It is listed in 4 states in all; the next are Arizona (875), Nevada (305) and Utah (14).
| # | State | Records | Share of state snakes | Rank in state |
|---|---|---|---|---|
| 1 | California | 1,923 | 2.6% | 8th of 46 |
| 2 | Arizona | 875 | 4.2% | 5th of 60 |
| 3 | Nevada | 305 | 7.6% | 4th of 27 |
| 4 | Utah | 14 | 0.4% | 19th of 28 |
When is the sidewinder seen?
Across the U.S., observation records of the sidewinder run mostly March through September, peaking in April with 19% of them. Almost none are from December to February.
Season by state
Among states whose main season falls within one calendar year, it starts earliest in March (California) and latest in April (Arizona). Each of these states peaks in a different month: April in California and July in Arizona.
| State | Main season | Peak month | Observation records |
|---|---|---|---|
| California | March through October | April | 201 |
| Arizona | April through September | July | 66 |
Where the sidewinder is recorded in each state
California
California holds 1,923 licensed records, the 8th most recorded of 46 snakes listed there. Its observation records in California run mostly March through October, peaking in April; most licensed records come from Riverside County, San Bernardino County and San Diego County. Next come Imperial County (207) and Inyo County (148).
Arizona
Arizona holds 875 licensed records, the 5th most recorded of 60 snakes listed there. Its observation records in Arizona run mostly April through September, peaking in July; most licensed records come from Maricopa County, Pima County and Yuma County. Next come Pinal County (105) and La Paz County (65).
Nevada
Nevada holds 305 licensed records, the 4th most recorded of 27 snakes listed there. Most of its licensed records in Nevada come from Clark County, Nye County and Lincoln County. Next come Esmeralda County (5).
Top counties in the U.S.
| # | County | State | Records | Share of U.S. |
|---|---|---|---|---|
| 1 | Riverside County | California | 537 | 17.2% |
| 2 | San Bernardino County | California | 533 | 17.1% |
| 3 | San Diego County | California | 329 | 10.5% |
| 4 | Maricopa County | Arizona | 252 | 8.1% |
| 5 | Pima County | Arizona | 241 | 7.7% |
| 6 | Clark County | Nevada | 213 | 6.8% |
| 7 | Imperial County | California | 207 | 6.6% |
| 8 | Yuma County | Arizona | 181 | 5.8% |
| 9 | Inyo County | California | 148 | 4.7% |
| 10 | Pinal County | Arizona | 105 | 3.4% |
| 11 | Kern County | California | 101 | 3.2% |
| 12 | Nye County | Nevada | 78 | 2.5% |
| 13 | La Paz County | Arizona | 65 | 2.1% |
| 14 | Los Angeles County | California | 61 | 2.0% |
| 15 | Mohave County | Arizona | 23 | 0.7% |
How recent are the sidewinder records?
The sidewinder record leans on older material: only 8% of dated U.S. records come from 2017–2026, and the median record is from 1966. The oldest dated record is from 1889; the busiest year was 1966, with 133 records.
| Decade | Records | Share |
|---|---|---|
| 1880s | 1 | 0.0% |
| 1890s | 16 | 0.6% |
| 1900s | 12 | 0.4% |
| 1910s | 21 | 0.8% |
| 1920s | 50 | 1.8% |
| 1930s | 301 | 10.9% |
| 1940s | 207 | 7.5% |
| 1950s | 353 | 12.8% |
| 1960s | 633 | 23.0% |
| 1970s | 283 | 10.3% |
| 1980s | 278 | 10.1% |
| 1990s | 148 | 5.4% |
| 2000s | 96 | 3.5% |
| 2010s | 194 | 7.0% |
| 2020s | 159 | 5.8% |
Species recorded in the same counties
Of the 23 counties where the sidewinder is most recorded, 23 are also top counties for each of the first four snakes in the table below; no other snake shares more. None of its closest neighbors is venomous.
| Species | Shared counties |
|---|---|
| California kingsnake | 23 |
| Gopher snake | 23 |
| Long-nosed snake | 23 |
| Western patch-nosed snake | 23 |
| Coachwhip | 21 |
| Desert nightsnake | 21 |
| Glossy snake | 21 |
| Western ground snake | 21 |
Related species in the U.S.
Other species of the genus Crotalus with profiles here: Western rattlesnake, Western diamondback rattlesnake, Prairie rattlesnake, Timber rattlesnake, Mohave rattlesnake, Red diamond rattlesnake, Black-tailed rattlesnake and Eastern diamondback rattlesnake.
GBIF records read 2026-09-29. Listed: any license. Counted: CC0/CC BY only. How we count.