Scorpions are venomous arthropods in the class Arachnida, relatives of spiders, solpugids, pseudoscorpions, mites, ticks, etc. They have eight legs, a long tail and a pair of pedipalps for capturing prey. At the end of the tail they are equipped with a stinger, fully loaded by a venom producing gland.
There are over 1400 species recognized today ranging from locations all over the globe. Most scorpions are adapted to live in deserts such as the Mohave, Sahara and Kalahari. A smaller percentage lives among the rainforests of Asia and Africa. Regardless of where the scorpion resides they key to their existence is all the same, the skilled art of an ambush predator.
Many enthusiasts, scientists and invertebrate dealers (especially in Arizona) use a common, universal and easy to understand tool that classifies the venom of scorpions. It is a simple numerical scale of 1-5 as shown below.
Level 1 (Virtually Harmless to Humans) – Level 5 (Extremely Dangerous if not Deadly to Humans)
All scorpions found in the United States fall at or below level 3. The Arizona bark scorpion Centruroides exilicauda is the highest the country has at level 3. However, in many states including Arizona, level 4 and 5 scorpions are legal for possession. These scorpions include yellow fat-tails, black fat-tails, death stalkers, and many others. They are extremely aggressive and will immediately posture in strike position upon irritation. Remember, one sting from a level 5 scorpion can and will most likely be fatal!
Arizona Bark Scorpion
- Scientific Name: Centruroides exilicauda
Adult Size: 2”-3”
Color: well distributed sandy yellow color, some with reddish pigment
Venom: level 3 !!!
Arizona bark scorpions Centruroides exilicauda are the most abundant and heavily encountered. They are also the most dangerous in the country. Small in girth, they have the ability to reach 3 inches in length and move very fast. They range all around the Phoenix area and in the majority of the state. They are one of the few species of scorpion that often climb the stucco walls of buildings and homes. This is a tactic they use for hunting small insects at night. Bark scorpions have a bad reputation with humans. There are many common scenarios that happen repeatedly which are easy to avoid. Most of them involve someone walking through the house at night or their neighbor cleaning up that pile of wood that’s been sitting out back for a year. Bark scorpions are particularly nervous creatures that strike first then run away after you’re jumping up in down in agony. So it’s best to plug in the old noggin and pay better attention next time you are fishing your hands around something.
Arizona Desert Hairy Scorpion
- Scientific Name: Hadrurus arizonensis
Adult Size: 3”-5”
Color: dark brown thorax with light yellow legs, tail, claws
Venom: level 1
Known for its voluptuous size and respectable length the Desert Hairy scorpion Hadrurus arizonensis is the largest found in United States. Adult size can scale to 4 sometimes 5 inches. Ranging through out many low land areas where sand is abundant and around populated locations as well. As a whole this species is not too hard to find. However, due to their shy demeanor finding one generally requires a little searching. Desert Harries prefer hiding during the day under rocks and other obstructions as they are nocturnal. Once darkness falls activity will spike as they venture out to feed.
Unlike pesky bark scorpions that are commonly found on building walls of residential areas Hairy scorpions prefer to stay low to the ground and out of the way. Their role around our living areas should be valued due to there veracious appetites. They will literally attempt to eat any living creature their size or smaller including the not so innocent bark scorpion. Normal diet involves spiders, centipedes, small vertebrates, scorpions, crickets, and many others.
For two reasons the venom associated with this species is quite harmless to humans. First, given that who ever is stung is not allergic, the sting from a Desert Hairy is similar to that of a bee’s and is quite harmless. A mild but irritating reaction with swelling can be expected. All Desert Hairy scorpions are considered to be a level 1 on the venom scale. Second, they are not commonly found in most housing communities and typically have specific localities they prefer to reside in.
Pale Desert Hairy Scorpion
- Scientific name: Hadrurus arizonensis pallidus
Adult Size: 3”-5”
Color: light brownish-yellow thorax with light yellow-green translucent legs and claws, light yellow tail, colors commonly vary with pallidus
Venom: level 1
The Pale Desert Hairy Hadrurus arizonensis pallidus is a type of color morph to the Standard Desert Hairy scorpion Hadrurus arizonensis. They appear nearly identical except for in color and translucency. Color typically ranges from a slight pale yellow to a bright beach sand yellow and can be easily singled out from the regular Desert Hairy scorpion. The venom from their sting is relatively mild same as an Arizona Desert Hairy. If stung, normally a bee sting-like reaction with mild swelling and redness can be expected. While all true scorpions are potentially dangerous this species is typically not found to be aggressive like many of its relatives. All Desert Hairy scorpions are considered a level 1 on the venom scale.
Stripe Tailed Scorpion
- Scientific Name: Vaejovis spinigerus.
Adult Size: 1”-2”
Color: dark tan, dark brown striations on thorax, distinct striping on tail
Venom: level 2
The Stripe Tailed scorpion though small in size, can pack one punch of a sting. Typically all small scorpions should be known for this trait. Only averaging around 2 inches in length this species is distinctly different from bark scorpions. Their bodies are substantially thicker with distinct lines that run up the length of the tails. They are burrowers that typically dig up to a meter deep in fine gravel/soil mix. Generally, encounters with this specie are slim unless living in a residence close to mountainous, rocky or desert landscape environments.
Vinegaroon (not a scorpion)
- Scientific Name: Mastigoproctus giganteus
Adult Size: 4”-6”
Color: Black with lighter gray in-between thorax and abdomen and on abdomen sides
Venom: (None) Uses acid based vinegar as a defense mechanism
The Vinegaroon is a true sheep in wolf’s clothing. These gentle giants are harmless only emitting the potent smell of vinegar when distressed. Also called Whip Scorpions from the skinny tail they use to do it with. Many of times mistaken as scorpions these arachnids are squished and stomped for no reason. However, they are more a friend to humans for eating up the pesky insects that get in the house.
Like a scorpion they have eight legs. Two of which are modified for sensory. Vinegaroons also use pedipalps as a means for catching prey. They are heavy burrowers and are only seen out at night. Due to their calm disposition they make wonderful pets for any bug enthusiast.
