Northern Pacific Rattlesnake

Snake, Rattle and Roll: Rattlesnake Season Is Here

Spring is here and with it brings warm weather and hot, dry conditions in many areas of California. Human encounters with snakes are more likely as these elusive animals become more active this time of year. Most native snakes are harmless. The California Department of Fish and Wildlife (CDFW) recommends avoiding the rattlesnake, a venomous species, and knowing what to do in the rare event of a bite.

Rattlesnakes may be found in diverse habitats, from coastal to desert, and are widespread in California. They can be attracted to areas around homes with heavy brush or vegetation, under wood piles where rodents may hide, as well as well-manicured landscapes to bask in the sun.

Rattlesnakes are not generally aggressive, unless provoked or threatened, and will likely retreat if given space.

“Snakes are often misunderstood. They provide significant ecosystem benefits, such as rodent control, and are an important part of California’s unique biodiversity,” said CDFW’s Conflict Programs Coordinator Vicky Monroe. “Snakes prefer to avoid people or pets and are not naturally aggressive. We encourage people to be rattlesnake safe, take time to learn about their local wildlife and take appropriate safety precautions when enjoying the outdoors.”

  • Most bites occur when a rattlesnake is handled or accidentally brushed against by someone walking or climbing.
  • Most bites occur between the months of April and October when snakes and humans are most active outdoors.
  • On occasion, rattlesnake bites have caused severe injury – even death.

The California Poison Control System notes that the chances of being bitten are small compared to the risk of other environmental injuries. The potential of encountering a rattlesnake should not deter anyone from venturing outdoors.

CDFW provides tips on its website to “Be Rattlesnake Safe,” how to safely coexist with native snakes and what to do (or not do) in the event of a snake bite.

Other resources can be found on the California Herps Living with Rattlesnakes web page.

In 2019, CDFW confirmed the state’s first case of Snake Fungal Disease (SFD), a newly emerging disease in snakes. SFD can cause significant mortalities in species of conservation concern. There is no evidence that SFD is transmittable from snakes to humans. You may assist CDFW’s efforts by reporting sightings of snakes with skin sores or unusual behavior. Do not attempt to touch or handle.

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Media Contacts:
Peter Tira, CDFW Communications, (916) 215-3858
Vicky Monroe, CDFW Statewide Conflicts Program Coordinator, (916) 856-8335

California kingsnake infected with Snake Fungal Disease

Snake Fungal Disease Detected in California

The California Department of Fish and Wildlife (CDFW) has confirmed the state’s first case of Snake Fungal Disease (SFD) in a California kingsnake (Lampropeltis californiae) from Plymouth, Amador County. The snake, which was emaciated and suffering from severe skin disease, was found by a member of the public on the side of the road and submitted for rehabilitation to Tri County Wildlife Care. Given its poor prognosis and the potential presence of SFD, the snake was humanely euthanized by CDFW’s Wildlife Investigations Laboratory and sent to the University of Illinois, where post-mortem examination and testing confirmed it was infected with the Ophidiomyces ophiodiicola fungus that causes SFD. In addition, this week the fungus was detected on the skin and in tissues from a Florida watersnake (Nerodia fasciata pictiventris) found deceased and collected by CDFW from Folsom, Sacramento County, suggesting the original case was not isolated.

SFD is a newly emerging disease in snakes. Cases may be mild to life-threating. Visible signs may include scabs, skin ulcers or nodules, crusted scales, discolored scales, cloudy eyes and a swollen or disfigured face. The infection may cause the upper layer of infected skin to shed repeatedly. Affected snakes are often emaciated, possibly due to decreased ability to capture prey, and often rest in open, unprotected areas where they are exposed to adverse weather and predators.

The Ophidiomyces ophiodiicola fungus lives in soil and can be transmitted to snakes through skin abrasions or through direct contact with other infected snakes. SFD can also be passed from mother to offspring at birth in some species. Snake species that share dens may be at higher risk than solitary species.

First characterized in 2008, SFD has been detected in more than 30 snake species in the U.S. and Europe. The fungus is present in at least 23 states, primarily in eastern states and the Midwest, although in 2018 it was also detected in Idaho and in southern Ontario, Canada. This detection in California is the furthest west the disease has been confirmed.

Although SFD has caused significant mortalities in species of conservation concern, such as the Timber Rattlesnake (Crotalus horridus) and federally threatened Eastern Massasauga (Sistrurus catenatus), other species may only exhibit mild infections.

It is unknown if SFD will impact snake populations in California. CDFW will be working with wildlife rehabilitators, academic and agency partners, and others who work with snakes to increase surveillance for SFD in California and implement appropriate precautions to minimize risk for human-caused spread among snakes. There is no evidence that SFD is transmittable from snakes to humans.

Although members of the public should avoid directly handling or disturbing snakes, they can assist CDFW’s efforts by reporting sightings of snakes with skin sores or unusual behavior.

As a reminder, releasing any animals that have been in captivity, even temporarily, requires prior written approval by CDFW.

More information on SFD is available at:

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Media Contacts:
Laura Patterson, CDFW Nongame Wildlife Program, (916) 341-6981

Dr. Deana Clifford, CDFW Wildlife Investigations Lab, (916) 358-2378
Kirsten Macintyre, CDFW Communications, (916) 322-8988