The striped bark scorpion and the closely related Baja California bark scorpion are also called bark scorpions.The Arizona bark scorpion (Centruroides sculpturatus, once included in Centruroides exilicauda) is a small light brown scorpion common to the Sonoran Desert in the southwestern United States and northwestern Mexico. An adult male can reach 8 cm in length (3.14 inches), while a female is slightly smaller, with a maximum length of 7 cm (2.75 inches).
Predators
Arizona bark scorpions are eaten by a wide variety of animals such as pallid bats,birds (especially owls), reptiles, and other vertebrates. Some examples include spiders, snakes, peccaries, rodents, and other scorpions. Development, pesticides and collecting scorpions for research or the pet trade also reduces the bark scorpion population.
The painful and potentially deadly venom of Arizona bark scorpions has little effect on grasshopper mice. Scientists have found the scorpion toxin acts as an analgesic rather than a pain stimulant in grasshopper mice.
Life cycle
Arizona bark scorpions have a gestation period of several months, are born live, and are gently guided onto their mother’s back. The female usually gives birth to anywhere from 25 to 35 young. These remain with their mother until their first molt, which can be up to three weeks after birth. Arizona bark scorpions have a life expectancy of about six years.
Arizona bark scorpions, like most other scorpions, are incredibly resilient. During US nuclear testing, scorpions, along with cockroaches and lizards, were found near ground zero with no recorded adverse effects.
Habitat
The Arizona bark scorpion is nocturnal,and particularly well adapted to the desert: layers of wax on its exoskeleton make it resistant to water loss. Nevertheless, Arizona bark scorpions hide during the heat of the day, typically under rocks, wood piles, or tree bark. Arizona bark scorpions do burrow, and are commonly found in homes, requiring only 1/16 of an inch for entry.
Arizona bark scorpions prefer riparian areas with mesquite, cottonwood, and sycamore groves, all of which have sufficient moisture and humidity to support insects and other prey species. The popularity of irrigated lawns, and other systems which increase environmental humidity in residential areas, has led to a massive increase in the number of these animals in some areas.
Centruroides scorpions are unusual in that they are the only genus in the Southwest that can climb walls, trees, and other objects with a sufficiently rough surface. Arizona bark scorpions practice negative geotaxis, preferring an upside down orientation, which often results in people being stung due to the scorpion being on the underside of an object.
The Arizona bark scorpion preys on small and medium-sized animals such as beetles, spiders, crickets, cockroaches, other insects and other scorpions.
The range of the Arizona bark scorpion is from southern California, southern Arizona, southern Nevada, extreme southwestern Utah and western New Mexico. They are also found in Baja California, Sonora and Chihuahua, Mexico.
- Size: Bark scorpions are relatively small compared to other scorpion species, typically measuring 1-3 inches in length. “Some can be quite large, up to three inches,” Hofstetter said. “But I would say a lot of them, we tend to see the young ones and they can be quite small, just an inch or two.”
- Color: “One of the ways to tell, and there are a lot of scorpions obviously in Arizona, but the bark scorpion tends to be on the smaller side and kind of a tan color,” Hofstetter said. Their coloration helps them blend in with their surroundings, especially on tree bark or rocky surfaces.
- Pincers: Bark scorpions have slender, elongated pincers that are typically lighter in color than their bodies. The pincers are used for grasping prey and defending against predators. “The pincers and stinger are fairly thin and the legs are thin. So that’s also a good way to tell them from some other scorpions,” Hofstetter said.
- Tail segment: An Arizona bark scorpion’s tail segment is thin and elongated, with a slender stinger at the tip. The stinger contains venom used to subdue prey and defend against threats.
- Behavior: Bark scorpions are nocturnal and seek shelter during the day in dark, protected areas such as under rocks, logs or debris. They are agile climbers and may be found on walls, ceilings or in trees.
Animal Fact Sheet: Bark Scorpion
Identifying Features
The bark scorpions (Centriroides exilicauda) body has two parts, a cephalothorax and abdomen. The tail is actually a part of the abdomen. It has five segments each longer than the last; at the tip is the stinger (not considered a segment). They have 8 jointed legs and a pair of pedipalps that are used for grasping prey and sensing.
Adaptations
Scorpions have “hairs” on their legs and other body parts that are sensitive to vibrations in the air. To avoid the extreme heat of the daytime they will shelter in the shade and come out at night to hunt for food. In the winter months they will hibernate, often congregating in large groups.
Habitat
The bark scorpion can be found in many places due to its ability to climb. It can be found not only under rocks or in rock crevices, but also in trees or high on rock walls. They also can be found inside of peoples dwellings trapped in sinks or bathtubs, climbing walls, or in a dark closet.
Range
The bark scorpion occurs from southern California through southern Arizona into western New Mexico; and in adjacent Mexico (Baja California, Sonora, and Chihuahua).
Wild Status
They are common and widespread throughout their range.
Diet
Scorpions are predators. They consume all types of insects, spiders, centipedes, and even other scorpions.
Predators
Scorpions are preyed upon by large centipedes, tarantulas, lizards, birds (especially owls), and mammals such as bats, shrews, and grasshopper mice.
Home
They prefer cool and moist areas and can be found in crevices, under pieces of bark, under rocks, under bricks and in houses.
Life Span
Scorpions live at least 2-6 years although many live much longer, especially in the wild.
Size
They are 2-3 inches long.
Are Arizona bark scorpions poisonous?
The Arizona Bark Scorpion can, and has, killed human adults, and it poses an even greater threat to children and the elderly. It’s venom delivers a powerful neurotoxin that can potentially be fatal. In fact, it’s the only scorpion in the United States that can kill.
How many people have died from bark scorpions in Arizona?
Two
Two recorded fatalities have occurred in the state of Arizona since 1968; the number of victims stung each year in Arizona and New Mexico is estimated to be in the thousands.
How bad are scorpions in Arizona?
Which scorpions are dangerous to people in Arizona? In North America, only one scorpion is dangerous to humans – the Arizona bark scorpion (Centruroides sculpturatus). It is small, just a couple inches in length, and is the only scorpion that produces envenomation syndrome.
What is the deadliest scorpion in the US?
Arizona bark scorpion
The Arizona bark scorpion (Centruroides sculpturatus) is the only deadly scorpion present in the U.S. Both its scientific and common names have changed throughout the years. Sometimes it is referred to as the “sculptured scorpion.” It can grow up to around 8 cm by the time it reaches its adult stage.
Arizona bark scorpion season: Where they hide and what happens if you get stung
As the desert heats up, scorpions — including the notorious Arizona bark scorpions — become more active, leading to more frequent sightings not only outdoors but in homes and other buildings.
These venomous arachnids are adept climbers and can be found in various habitats, including desert scrubland, urban areas and suburban neighborhoods. While bark scorpions are not typically aggressive, their sting can cause painful symptoms, especially in vulnerable populations such as young children or older adults.
Here is everything you need to know about the Arizona bark scorpion, including how many people have died from being stung.
And if you’re curious about other common Arizona creatures, check out our guides to black widow spiders, cicadas and palo verde beetles.
How common is the Arizona bark scorpion?
The Arizona bark scorpion is common in the Southwestern United States, particularly in Arizona, as its name suggests. It is one of the most frequently encountered scorpion species in the region.
It is well adapted to arid environments and can be found in a variety of habitats, including desert scrubland, rocky outcrops, urban areas and even inside homes.
How painful is an Arizona bark scorpion sting?
The pain from an Arizona bark scorpion sting is often described as intense and immediate.
“They are the most venomous scorpion in North America. So, very painful and the venom can last up to two days,” Hofstetter said. “It’s worse than a bee sting and people compared to like an electric shock or something like that. You can be disoriented or you can get numb in the area that’s been stung.”
The pain usually begins to subside within a few hours to a day. People may experience prolonged or more severe symptoms if they are particularly sensitive to the venom or if the sting occurs in a sensitive area of the body, such as the hands or feet.
Identify a Bark Scorpion
Learn how to identify Bark Scorpions! There are more than 30 different species of scorpions throughout the Phoenix, AZ Valley. The most venomous are Bark Scorpions.
Physical Identification
Arizona Bark Scorpions have a tiny little bump or “subaculear tooth” that pokes out of an Arizona Bark Scorpions tail just under the stinger. (You may need a magnifying glass to see it.)
Bark Scorpions have a more sender body build with thinner tails and pincers than other scorpion species.
2 dark eyes on top of head, above 3 pair of lateral eyes.
Mature Bark Scorpions measure 2.7 – 3.1 inches long from head to stinger.
Coloring is tan, but ranges from all yellowish brown without any markings to striped with stripes running from head to tail. Right after Bark Scorpions molt it is a darker yellowish almost orange tan color.
Behavioral Identification
Scorpions in Arizona, including Bark Scorpions, live all year long, and survive the coldest temperatures our desert has. Bark Scorpions are the only scorpions that are willing to co exist with other scorpions. In the winter, Bark Scorpions actually gather in large groups to nest!
Unless you’re a scientist or don’t have a magnifying glass handy, the easiest way to tell if what you have is a Bark Scorpion is by watching its behavior!
The Bark Scorpion will lay its tail down – parallel to the surface it is on {but still curled up} while waiting for prey to come along.
Other scorpion species in Phoenix AZ actually keep their tail up above their backs while resting.
Can scorpions climb walls? Yes, Bark Scorpions love to climb {they climb trees bushes, stucco siding, block walls, interior walls, etc} and often position themselves upside down.
Bark Scorpions are nocturnal, and attracted to moist areas that are cool, and areas with an air flow. That’s why Bark Scorpions love cracks of block wall fences, and inside homes.
