The fattail scorpion is a genus of scorpion known by the scientific name Androctonus. They are perhaps best known for the toxicity of their venom, which among the deadliest of any scorpion in the world, able to kill a human in about seven to eight hours. That makes these scorpions among the deadliest animals in the world. They come in many different colors and can be different sizes, but all range from about four to ten centimeters long. These scorpions are born as scorplings, and periodically molt as they grow, to shed their old exoskeleton and move into a newer one. The fattail scorpion finds its home in the desert areas of Northern Africa and the Middle East, but most any warm climates with rocky areas will due.
The body design of the fattail scorpion has a beautiful look to it. These scorpions range from about four to ten centimeters long. The fattail scorpion's body can be divided into the cephalothorax and the abdomen. The cephalothorax is the scorpions head. The cephalothorax has six pairs of appendages and a pair of eyes on top, with a few other pairs of eyes on the corners of their head. The head is also covered by a carapace, which is basically the upper part of the exoskeleton. The mesosoma is the front part of the abdomen. This is made up of six segments. The first segment mainly has the reproductive organs. The second segment has some sensory structures called pectines, and all of the other segments have book lungs for respiration.  Although the fattail scorpion has a few different types of species in the genus Androctonus, and they differ in color, most all of the scorpions can be identified by their fat tails. Most other scorpion species have a smaller tail(or stinger), but the fattail scorpion, as the name says, has a much thicker tail.
The tail of the fattail scorpion is extremely venomous. In fact, the fattail scorpion is one of the more poisonous scorpions in the worlds. The tail is covered in tiny setae that act as sensory detectors.  The tail of this scorpion is the reason it is such an extremely venomous and deadly scorpion. If a human is stung by the tail, they could die but still have a good chance of living. The tail of the scorpion is unusually fat, which can help it be recognized. This genus cannot easily be identified by color, because the difference in color is immense. The Androctonus australis is a light yellowish color, while the Androctonus crassicauda is a dark brown or blackish color. The main means of identification for this genus of scorpion is the unusually large tail, because other scorpions have much thinner tails. In extremely rare cases, scorpions in general can be born with two tails. However, this is not a different species of scorpion, but merely an abnormality in that scorpion.
The life cycle of a fattail scorpion is quite common. This scorpion, like most others, reproduces sexually. The Androctonus genus has both male and female genders, so that makes it a little less complicated. The male finds the female, and after some pre-mating rituals, they begin to mate. First, however, the male leads the female to a suitable place to lay his spermataphore. The female then moves over this, allowing it to enter her, releasing the sperm, fertilizing the female. The male then quickly retreats to avoid being eaten by the female. The female later gives birth to scorplings. Scorplings(baby scorpions) are born one by one. The litters average around eight members, but can vary from two all the way up to 100.
Once born, a Fattail scorpion can live from four all the way to twenty-five years. Once the scorpling is born, it stays on its mother's back until it finally molts. A scorpling cannot survive before its first molt without its mother, because it's in a fragile state and depends on the mother for regulating the moisture levels. Then the young scorpion continues to molt in order to continue growing. To grow, the scorpion molts periodically. Once the scorpion molts, it is very vulnerable because of its fragile exoskeleton, but that grows back. As the exoskeleton is growing back, the scorpion has to stretch in order to make sure it can move once it is in the final molt. After about five to seven molts, the scorpion is considered to have reached maturity. New exoskeletons are not fluorescent, but the florescence comes back as does the exoskeleton(scorpions with complete exoskeletons are fluorescent under a blacklight)
The fattail scorpion finds its home in the desert or the semi-desert areas found in northern Africa and the Middle East. However, they can be found all the way from Mauritania to India, from Turkey to Togo. They can make their home mostly in the areas of the Arabian and Sahara deserts. A warm climate is good for them, but considering they are from the desert, temperature drops do not disturb them, as the desert ranges from extremely hot during the day to very cold at night. The fattail scorpion makes its home in a rocky, hot and arid area. These areas often have many flat, dry rocks for the scorpions to use as cover. While in these habitats, the scorpions feed mainly off of cockroaches and other species that use human dwellings for homes. 
The temperature of all these climates ranges from around 60 to 90 degrees Fahrenheit. Rain is very low in these areas, which is good for the fattail scorpion. It prefers to be under rocks or under some surface, where it can use the surface for cover. Fattail scorpions, as well as other scorpions, like to be near humans and in their households, hiding in dark corners and such. However, they mainly just prefer dry warm areas. It shelters in the day in burrows dug in the sand, but can also be found under loose stones, logs, rubble, in between cracks or bricks, and like said before, in houses. 
Venom from the fattail scorpion genus can be very deadly. Species differ in harm, but the most deadly scorpion in this genus is the arabian fattail scorpion. The yellow fattail scorpion is also deadly, but not quite as deadly as the arabian fattail.  The venom from the yellow fattail scorpion is as poisonous as a cobra's. It possesses the ability to kill a dog in around seven minutes. This venom can also kill a human, but that takes around six to seven hours. In Mexico alone, around 8000 people die every year from scorpion stings in general. This does not mean the fattail scorpion specifically, but all scorpions. The key that makes this venom deadly is the neurotoxins. These neurotoxins affects the nervous system, which paralyzes prey. However, as most people view this as a weapon, the main function of these stingers is defense. .
In fact, the term "Androctonus" means man-killer. It is actually strongly debated that the Androctonus genus is the most deadly scorpion on the planet, rivaling with the Arabian deathstalker. The venom of the Androctonus genus differs in exact components. The australis species is said to have LD50 values of 32 and 75 percent( LD50 means lethal dose, 50 percent)  However, these venoms can also be good for humans, if used correctly. For example, in the species Androctonus crassicauda, the venom can decrease cellular viability in neuroblastoma and in breast cancer cells. 
This video shows the Androctonus australis capture and then paralyze its prey.
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- Androctonus crassicauda venom limits growth of transformed cells "ScienceDirect" December 12, 2012 (Date-of-access)