Diamondback water snake (Nerodia rhombifer)
The diamondback water snake is a non-venomous snake in the family Colubridae. GBIF holds 6,119 licensed U.S. records of it; it reaches our listing threshold in 12 states, most of all Arkansas (3,056), Texas (1,612) and Oklahoma (506). Its observation records peak in April.
Nerodia rhombifer, commonly known as the diamondback water snake, is a species of nonvenomous natricine colubrid endemic to the central United States and northern Mexico. There are three recognized subspecies of N. rhombifer, including the nominotypical subspecies.
From Wikipedia: Nerodia rhombifer, text under CC BY-SA 4.0.
Is the diamondback water snake poisonous or venomous?
No. The diamondback water snake is non-venomous: it belongs to the family Colubridae, not to the pit vipers or coral snakes, the only U.S. land snakes with medically dangerous venom. It may bite if handled; clean the bite like any small wound.
Often mistaken for
The diamondback water snake is non-venomous, but people often take it for cottonmouths (both are recorded in 11 of its 12 states).
Which states have the diamondback water snake?
Records are spread over 12 states; the top three, Arkansas, Texas and Oklahoma, hold 85% of them. It is the most recorded snake of all in Arkansas.
| # | State | Records | Share of state snakes | Rank in state |
|---|---|---|---|---|
| 1 | Arkansas | 3,056 | 58.1% | 1st of 36 |
| 2 | Texas | 1,612 | 3.9% | 8th of 86 |
| 3 | Oklahoma | 506 | 3.8% | 7th of 50 |
| 4 | Louisiana | 296 | 5.9% | 5th of 41 |
| 5 | Kansas | 188 | 1.3% | 26th of 44 |
| 6 | Alabama | 156 | 2.7% | 13th of 44 |
| 7 | Mississippi | 115 | 6.2% | 4th of 38 |
| 8 | Tennessee | 67 | 2.6% | 12th of 32 |
| 9 | Missouri | 57 | 3.0% | 11th of 36 |
| 10 | Indiana | 28 | 1.3% | 19th of 27 |
| 11 | Illinois | 26 | 0.9% | 20th of 33 |
| 12 | Kentucky | 4 | 0.3% | 22nd of 24 |
When is the diamondback water snake seen?
Across the U.S., observation records of the diamondback water snake run mostly March through October, peaking in April with 24% of them. Winter (December to February) holds 5% of them.
Season by state
Observation records run through most of the year in Louisiana. Among states whose main season falls within one calendar year, it starts earliest in March (Arkansas and Texas) and latest in May (Missouri). The most common peak month is May, shared by Arkansas, Kansas, Missouri and Oklahoma.
| State | Main season | Peak month | Observation records |
|---|---|---|---|
| Texas | March through October | April | 631 |
| Louisiana | most of the year | April | 82 |
| Missouri | May through October | May | 51 |
| Arkansas | March through October | May | 46 |
| Oklahoma | April through September | May | 46 |
| Kansas | April through July | May | 33 |
Where the diamondback water snake is recorded in each state
Arkansas
Arkansas holds 3,056 licensed records, the most recorded of 36 snakes listed there. Its observation records in Arkansas run mostly March through October, peaking in May; most licensed records come from Lonoke County, Columbia County and Pulaski County. Next come Greene County (8) and Poinsett County (8).
Texas
Texas holds 1,612 licensed records, the 8th most recorded of 86 snakes listed there. Its observation records in Texas run mostly March through October, peaking in April; most licensed records come from Parker County, Brazos County and Travis County. Next come Dallas County (64) and Bexar County (52).
Oklahoma
Oklahoma holds 506 licensed records, the 7th most recorded of 50 snakes listed there. Its observation records in Oklahoma run mostly April through September, peaking in May; most licensed records come from Cleveland County, Marshall County and McCurtain County. Next come Comanche County (33) and McClain County (24).
Louisiana
Louisiana holds 296 licensed records, the 5th most recorded of 41 snakes listed there. Its observation records in Louisiana run through most of the year, peaking in April; most licensed records come from East Baton Rouge Parish, East Carroll Parish and Saint Tammany Parish. Next come Iberia Parish (16) and Avoyelles Parish (12).
Kansas
Kansas holds 188 licensed records, the 26th most recorded of 44 snakes listed there. Its observation records in Kansas run mostly April through July, peaking in May; most licensed records come from Barton County, Douglas County and Woodson County. Next come Lyon County (11) and Stafford County (10).
Alabama
Alabama holds 156 licensed records, the 13th most recorded of 44 snakes listed there. Most of its licensed records in Alabama come from Baldwin County, Macon County and Tuscaloosa County. Next come Greene County (13) and Washington County (9).
Mississippi
Mississippi holds 115 licensed records, the joint 4th most recorded of 38 snakes listed there. Most of its licensed records in Mississippi come from Lafayette County, Harrison County and Oktibbeha County. Next come Adams County (6) and Tishomingo County (5).
Tennessee
Tennessee holds 67 licensed records, the 12th most recorded of 32 snakes listed there. Most of its licensed records in Tennessee come from Lake County, Obion County and Shelby County. Next come Hickman County (3) and Henry County (2).
Missouri
Missouri holds 57 licensed records, the 11th most recorded of 36 snakes listed there. Its observation records in Missouri run mostly May through October, peaking in May; most licensed records come from Holt County, Lincoln County and Stoddard County. Next come Pemiscot County (3) and Pike County (3).
Top counties in the U.S.
| # | County | State | Records | Share of U.S. |
|---|---|---|---|---|
| 1 | Lonoke County | Arkansas | 2,982 | 48.7% |
| 2 | Parker County | Texas | 109 | 1.8% |
| 3 | Brazos County | Texas | 90 | 1.5% |
| 4 | Travis County | Texas | 78 | 1.3% |
| 5 | Cleveland County | Oklahoma | 68 | 1.1% |
| 6 | Dallas County | Texas | 64 | 1.0% |
| 7 | Marshall County | Oklahoma | 59 | 1.0% |
| 8 | Bexar County | Texas | 52 | 0.8% |
| 9 | East Baton Rouge Parish | Louisiana | 51 | 0.8% |
| 10 | Lake County | Tennessee | 44 | 0.7% |
| 11 | Lafayette County | Mississippi | 43 | 0.7% |
| 12 | McCurtain County | Oklahoma | 40 | 0.7% |
| 13 | Harris County | Texas | 39 | 0.6% |
| 14 | Baldwin County | Alabama | 36 | 0.6% |
| 15 | Barton County | Kansas | 36 | 0.6% |
How recent are the diamondback water snake records?
The diamondback water snake record leans on older material: only 16% of dated U.S. records come from 2017–2026, and the median record is from 1994. The oldest dated record is from 1860; the busiest year was 1995, with 752 records.
| Decade | Records | Share |
|---|---|---|
| 1860s | 2 | 0.0% |
| 1870s | 1 | 0.0% |
| 1880s | 19 | 0.3% |
| 1890s | 3 | 0.1% |
| 1900s | 30 | 0.5% |
| 1910s | 27 | 0.5% |
| 1920s | 114 | 1.9% |
| 1930s | 156 | 2.6% |
| 1940s | 209 | 3.5% |
| 1950s | 225 | 3.8% |
| 1960s | 407 | 6.9% |
| 1970s | 243 | 4.1% |
| 1980s | 175 | 2.9% |
| 1990s | 3,069 | 51.7% |
| 2000s | 163 | 2.7% |
| 2010s | 360 | 6.1% |
| 2020s | 734 | 12.4% |
Species recorded in the same counties
Of the 128 counties where the diamondback water snake is most recorded, 61 are also top counties for the plain-bellied watersnake, more than for any other snake. Venomous species among its neighbors: the northern cottonmouth.
| Species | Shared counties |
|---|---|
| Plain-bellied watersnake | 61 |
| Rough greensnake | 51 |
| Speckled kingsnake | 50 |
| Eastern racer | 49 |
| DeKay's brown snake | 48 |
| Northern cottonmouth venomous | 45 |
| Western rat snake | 43 |
| Common garter snake | 41 |
Related species in the U.S.
Other species of the genus Nerodia with profiles here: Northern water snake, Southern watersnake, Plain-bellied watersnake, Brown water snake, Green water snake, Salt marsh snake and Florida green water snake.
GBIF records read 2026-09-29. Listed: any license. Counted: CC0/CC BY only. How we count.