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Western Patch-nosed Snake
This is the snake most people in the desert Southwest see for about two seconds and then never identify. It is fast, it is alert, it is out in the middle of the day, and it is gone before you have finished looking at it, which is why it gets filed away as a racer or a whipsnake and forgotten. The thing that actually settles it takes one glance at the right place: the tip of the nose. Western patch-nosed snake carries a large triangular scale over the end of its snout with edges that lift free of the scales around it, and California's own state assessment says that scale plus the pale stripe down the back is enough to separate this snake from every other snake in its range. What the patch is for is the interesting part, and the question is not closed. Two sources state flatly that the snake uses it to sniff out and dig up buried reptile eggs, including the eggs of other snakes. California's 2016 assessment hedges the same claim and notes the behavior has never been documented in its coastal population at all. Both versions are worth carrying. So is the diet fact behind them, which is narrower and stranger than the one usually printed: this snake does not mainly eat eggs. It mainly eats whiptail lizards, and it appears to pick prey by how fast the prey is moving.

Seasonal Timeline

Western patch-nosed snakes are day-active and out in the open, with a broad season running March into October. California's two state accounts both put the peak in May and June; no Southwest source names a peak month at all, and Arizona accounts instead describe the snake as out earlier in the spring and later in the fall than the other snakes around it. Whether it goes dormant depends on where you are: high and cold sites see a real winter shutdown, while low desert and coastal southern California produce surface records in almost every month of the year.

Peak, SouthwestMar–Jun
JanFebMarAprMayJunJulAugSepOctNovDec

Western patch-nosed snakes are day-active and out in the open, with a broad season running March into October. California's two state…

Three sources describe the winter differently, and all three are right about different ground. An Arizona-wide account states the species hibernates during late fall and winter. A museum account says it is active in the daytime year round in warmer climates, and gives an early April to early November season only in milder ones. California's own life history account says snakes may be active all year in the southern part of the state in mild to warm weather. Those are three points on an elevation and latitude gradient rather than a genuine disagreement, but a reader who finds all three deserves to be told that instead of handed one of them.

The month-by-month record is unusually good for a snake this poorly studied. In the Tucson region, this species has been found in every month of the year except January, and it is specifically noted for basking and being active earlier and later in the year than the other snakes around it. In coastal southern California, specimens appear in the published literature in every month except January and February, and federal pitfall trapping between 1995 and 2011 filled even that gap with three January captures and one February capture. Warm and presumably active animals have been found under stones in Ventura County between January and March. Animals found in December and January inside gopher burrows and woodrat nests were cold and presumably dormant.

May and June is the window that matters, and the evidence for it is specifically California. Both California state accounts name those two months independently. No published Southwest source names a peak month at all, so the peak stands as a California finding rather than one extended across the range. It does line up with the breeding calendar: mating April to June, gravid females found May through August, eggs incubating about 85 days in the one laboratory record that exists, and hatchlings appearing from July into October.

Where They're Found

Its range covers two regions: the Southwest and California. The California part of the range rests on two California state agency sources and three federal park records.

Arizona is the core of the range. An Arizona-wide account puts the species across southern Arizona below the Mogollon Rim, along the western edge of the state, and through the northern plateau deserts, running from near sea level on the Colorado River up to about 6,500 feet, in everything from flatlands and low valleys to rocky bajadas, foothills, and mountain slopes. Federal park species records back that up across the state, at Saguaro, Organ Pipe Cactus, Grand Canyon, Chiricahua, Tonto, Tumacacori, Montezuma Castle, Tuzigoot, Walnut Canyon, and Wupatki.

Nevada and Utah are confirmed through federal park records and, for Utah, through the state's own rulebook. Federal records place the species at Lake Mead National Recreation Area and Tule Springs Fossil Beds National Monument in Nevada, and at Zion National Park, Glen Canyon National Recreation Area, and Rainbow Bridge National Monument in Utah. Utah names the species by its full scientific name in its own reptile and amphibian possession rules, which is independent confirmation the state treats it as a Utah animal. Range summaries run the species as far north as northwestern Nevada.

New Mexico is claimed, with a caveat attached. Federal park records list the species at Carlsbad Caverns National Park and White Sands National Park. Both rest on the older treatment of the Big Bend form as a subspecies of this species. If the 2021 revision described below holds, New Mexico's animals belong to a different species and this state needs re-checking.

California is a real addition, not a rounding of the map. The state maintains a full life history account describing the species as widely distributed through the lowlands of southern California from the coast to the eastern border, up to 2,120 meters, about 7,000 feet, ranging north through desert habitats in Owens Valley and reaching the vicinity of Honey Lake in Lassen County. A separate state species assessment covers the coastal form from Ventura and Los Angeles Counties south to the Mexican border, from sea level up to 2,130 meters. Federal park records add Death Valley National Park, Joshua Tree National Park, and Mojave National Preserve. Joshua Tree's own reptile list is precise about which form is where: the Mojave patch-nosed snake is rated common on sandy valley floors in the park's northern section, while the desert patch-nosed snake is rated rare in creosote bush scrub and desert washes in the southern section.

Texas is deliberately left off, and the reason is a live taxonomic dispute. A federal park record does list this species at Big Bend National Park in Texas. That record depends on treating the Big Bend patch-nosed snake as a subspecies of Salvadora hexalepis. A curated taxonomic database, following a 2021 morphological revision of the genus, treats it instead as a separate species, Salvadora deserticola. Arizona-facing sources still list it as one of three Arizona subspecies. If the revision holds, this species does not reach Texas at all, and it has no South Central presence. The same uncertainty is why the New Mexico claim above carries a caveat.

Subspecies counts do not agree either. The federal taxonomic record lists three: the desert, Mojave, and coast patch-nosed snakes. The curated taxonomic database lists four, adding Klauber's patch-nosed snake of Baja California. Arizona sources list three for Arizona alone, including the Big Bend form. None of that changes which snake is in your yard, and the enlarged nose scale identifies all of them.

Habitat splits by form, which is worth knowing before you go looking. The desert forms are open-country animals: creosote bush flats, Sonoran desertscrub, washes, sandy flats, rocky bajadas, grassland, sagebrush, and pinyon-juniper woodland as high as 7,000 feet. The coastal California form is the opposite, showing an apparent preference for brushy chaparral. One historical survey located 35 specimens in heavy brush and chaparral, more than in all other habitat types combined, and unpublished state data describe a preference for chamise and red shank with the snake often basking at or near the tops of bushes. Same species, genuinely different cover, and it changes what advice makes sense in each region.

Everywhere else is out. No published source places this species in the Mountain West, the Midwest, the Northeast, the Southeast, or the Pacific Northwest. It is a warm-desert animal of the southwestern United States, northwestern Mexico, and Baja California, including several Pacific and Gulf of California islands.

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