The Myths of Mount Diablo's  "Deadly Big Four"

by Naturalist Michael Marchiano

Mount Diablo is home to an array of many extraordinary plants, animals, habitats, geological formations, and mico-environments. Rarely seen animals as large as a mountain lion, as elusive as a night snake, and as fleeting as a Ceanothus Moth are not seen by the average visitor or casual hiker.

 

Among this fabulous fauna are four creatures that have come to notoriety through folk lore, mythology, and undeserved bias.

 

First and foremost on this list is the California Tarantula (Aphonopelma iodus). Many visitors to the park are surprised to discover that tarantulas reside here at all. Those that visit the mountain in late summer and early fall (mating season for these benign giants) often see the males crossing a road or path looking for a female in her burrow.

 

Contrary to popular belief, these gentle arachnids are completely harmless to humans. Actually, there is NO tarantula known world wide that is deadly to man. There are a few African and Asian species that have a painful bite, but no one has ever died from a tarantula bite.

 

People often compare a tarantula bite to a bee sting. However, this is absolutely false. Having experienced both, I would allow ten tarantulas to bite me before allowing one bee to sting me. Bee stings are very painful, burn, cause swelling, and last for two to three days. Tarantula bites do none of these.

 

These magnificent and slow-moving spiders, although commonly portrayed as threatening, dangerous, and monstrous in the media and movies, are none of the above and have been unjustly vilified.

 

Another creature with an undeserved reputation is our local scorpion. Most visitors never see or come in contact with scorpions and actually are quite surprised when they find out we have at least three species living on Mount Diablo. The most common is the California Forest Scorpion (Uroctonus mordax). Growing up to two inches long, it is the largest in the area. Once again, its ability to inflict a “deadly” sting is a complete fabrication. NONE of the three local species can inflict a sting of any consequence to a human being. The forest scorpion sting feels like a mild burning sensation and lasts for no more that 15 minutes, usually less. The only way to get stung is to grab or step on a scorpion barefoot.

 

Scorpions only come out at night to hunt for other scorpions, insects, and small arthropods. If you wish to see these fascinating creatures, join one of our summer night hikes and you will be surprise when we use an ultra-violet flashlight to locate them and cause them to glow in the dark.

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Next on our list of the feared and “deadly” is the only spider of any medical significance in Contra Costa County, the “notorious” Western Black Widow (Lactrodectus hesperus). This shiny black spider with a red hourglass shape on its underside is ubiquitous through out Contra Costa County and can be located on Mount Diablo around any campground, building, out house, or wood pile. It is another night time hunter, staying well hidden near its web during the day and then pouncing on unsuspecting insects that get too close to its web at night. It likes dark, undisturbed places.

 

Once again, the Black Widow's bite is way overrated. Although its venom is very toxic, it has such a small quantity that often its bite has no or only mild effects on a person. In severe cases, maybe involving a child or an immune-compromised individual, the venom can cause pain, red lines extending from the bite, and flu like symptoms such as achy muscles, headache, and nausea. Rarely is anti-venom used because it commonly can cause anaphylactic shock, which causes death more often than the bite itself. In the past 37 years, the CDC does not have a record of one confirmed death from a Black Widow in over 50,000 reported incidents each year in the United States. Like each of the above, these beneficial creatures just want to be left alone and rightly fear us far more than we should ever fear them.

 

The last of our “Big Four” creatures of “death” is the Northern Pacific Rattlesnake (Crotalus oreganus), the ONLY venomous snake in Northern California. Once again, this is a non-aggressive creature who wishes to avoid contact with humans.

 

We have very few bites here on Mount Diablo, especially considering that this is one of our most common snakes. Most bites are caused when someone reaches for the snake (not a bright idea) or on a rare occasion when someone steps on a snake inadvertently.

 

The bite of this animal should always be considered serious and checked out medically. Although there are very few deaths caused by venomous snakes in the United States, there is plenty of serous pain, suffering, and other temporary discomfort from a bite.

 

Once again, the actual numbers undermine the deadly reputation of this fascinating serpent. Out of approximately 10,000 venomous snake bites annually in the United States, there are only 10-12 deaths, half of which are from members of religious cults who handle deadly snakes and will not seek medical attention if bitten.

 

Rattlesnakes as well as several other local snakes help to keep rodent populations in check and in turn become food for larger predators. They are an integral part of our Mount Diablo ecosystem.

 

Each of the above creatures has its place in the natural order. When you learn about their fascinating lives and their relationship to the rest of the environment, you will no longer fear these animals but instead respect them.

Tarantula | Debbie McKeown

Scorpion | Denise Wight

Western Black Widow | Michael Marchiano

Northern Pacific Rattlesnake | Michael Marchiano

© 2019 by Mount Diablo Interpretive Association