Scorpions‘ ancestors first appeared around 450 million years ago. That’s as old as sharks, older than dinosaurs, and even older than trees. Scorpions evolved from these early arthropods, known as Eurypterids or giant sea scorpions. The massive creatures lived in the ocean and grew over eight feet long. Fortunately for us, modern scorpions average no more than several inches long, which is a good thing considering they pack potent venom.
Scorpions can be found around the world on every continent except for Antarctica.
©Nick Greaves/Shutterstock.com
What Were Early Scorpions Like?
Eurypterids, ancestors of scorpions, were the largest arthropods that ever lived. Sea scorpions looked very much like today’s scorpions, but swam in the ocean. These formidable predators were at the top of the food chain, feasting on large fish and also on each other. Eurypterids are thought to be the ancestors, not only of today’s scorpions, but possibly all arachnids.
Sea scorpions lived 450 million years ago, preying on large fish and trilobites.
©Aunt Spray/Shutterstock.com
A fascinating video on YouTube from BeSmart by PBS explains that at some point, eurypterids left the ocean for land and became amphibians. During this time, they preyed on spawning fish leaping out of the water, much like bears do today. Over time, today’s scorpions evolved into the much smaller and less deadly size that they are today.
How Have Scorpions Survived for Hundreds of Millions of Years?
Scorpions are in the class Arachnida, along with mites, spiders, and ticks. There are over 2,000 species of scorpions, and they all have incredibly impressive survival skills. For one thing, a scorpion’s sting can inflict a lot of damage. There are around 30 to 40 scorpion species that have enough venom in their sting to kill a person. The only scorpion in North America with that strong venom is the Arizona bark scorpion.
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Scorpions have evolved venom that perfectly targets whatever species they prey on.
©Be Smart / YouTube – Original
Aside from an impressive defense, scorpions have also adapted to be able to survive the harshest of environments. They can live in both hot and cold environments. When resources are scarce, they slow their metabolisms to require less food.
Scorpions have also had an evolutionary advantage. As the BeSmart video explains, the common ancestor of scorpions created a second genome, which is a copy of every single gene in their body. This way, scorpions could evolve with mutations that might normally be negative, but the second copy kept them healthy. However, the more they mutated and mutations built up, they sometimes transformed into, as the video explains, “something that’s really powerful.” For example, producing “venom that can effectively keep you from being eaten by your predators.”
Where Do Scorpions Live Today?
Scorpions live on every continent in the world except for Antarctica. Most can be found in arid deserts, but others thrive in tropical and lush rainforests. They typically spend their days hiding in burrows, coming out at night to hunt their prey.
In the U.S., scorpion populations are largest in southwestern states such as Texas, Arizona, New Mexico, and California. However, scorpion species can be found in 29 states around the country.
How Dangerous Are Scorpions?
Although a scorpion sting can be very painful, and even fatal, scorpions aren’t actively looking to sting. They are shy, staying hidden in burrows or under bark and tree leaves, waiting for their prey to walk by. However, if a scorpion does feel threatened, and stings a person, their venom can be extremely painful and deadly. According to BeSmart, “scorpion venom is perfectly evolved to make nervous systems go haywire.”
Their venom does this by using peptides, which are protein segments. These peptides are neurotoxins that signal your brain that something terrible is wrong with your body. Even one drop of venom can cause excruciating pain, making your brain think you’ve been, according to BeSmart, “smashed with a sledgehammer,” or “electrocuted.”
The video explains that scorpion venom has 250 unique components that are used for various reasons. They may be used for defense by targeting a mammal’s nervous system, or for paralyzing insects so they can eat them. Their venom also helps break down the insect’s body, liquefying it to make it easier for the scorpion to eat.
What Is the Most Venomous Scorpion in the World?
The deathstalker (Leiurus quinquestriatus) is in the “Guinness Book of World Records” for having the most venomous sting of any scorpion on earth. This dangerous scorpion lives in North Africa and the Middle East. However, despite the deadly cocktail that makes up this scorpion’s venom, its venom is used as medicine for a variety of conditions, including cancer, malaria, and tuberculosis. Nearly as potent are fat-tailed scorpions (Androctonus), which are native to Africa.
How Might Scorpion Mice Help Human Medicine?
Grasshopper mice, or scorpion mice, have evolved to be not only immune to scorpion venom, but their bodies also block the pain of the sting. These mice prey on scorpions without any ill effects from the stings. Scientists are studying how grasshopper mice can block pain signals. This would have huge implications for people with chronic pain, and could perhaps replace opioids.
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