Scorpions are among the oldest land animals on Earth, with fossil evidence of their existence dating back 430 million years. They are arachnids, closely related to spiders, ticks and mites. Scorpions are larger than most other species in their class. Some species, such as the emperor scorpion of West Africa, can grow to 25 cm in length (10 in). They have eight legs, two claw-like pincers known as pedipalps, two main body regions, and a venomous stinger at the tip of a segmented tail.
But what has made this prickly predator so successful? Here are five facts about scorpions that explain their evolutionary longevity.
1. They Can Survive Almost Anywhere
Scorpions can be found on every continent on Earth, except Antarctica. Most species of scorpion inhabit desert-like climates. The Arizona hairy scorpion is one such example, specially adapted to hot and dry conditions. The Arizona hairy scorpion, which can be found in the Sonoran and Mojave deserts of Mexico and the southwestern United States, dig elaborate burrows (up to 8 feet deep), coming out at night to hunt insects, spiders and small vertebrates.
When the weather gets cold, some scorpions, such as the bark scorpion (also endemic to the southwestern United States and northern Mexico), will nest and hibernate in large groups to conserve warmth.
As a testament to their survivability, research shows that scorpion populations were mostly unaffected by nuclear testing conducted in the Nevada desert in the 1960s.
2. Their Venom Is Among The Most Potent In The Entire Arachnida Class
Arachnida is a class of joint-legged arthropods which includes species such as scorpions, ticks, mites, pseudoscorpions, harvestmen, and whip scorpions. While many species of arachnids are venomous, scorpions boast an especially potent venom cocktail. Each year, scorpion stings contribute to over 3,000 human deaths worldwide.
One particularly deadly scorpion is the deathstalker (Leiurus quinquestriatus), found in North Africa, the Middle East, and parts of Asia. A sting by a deathstalker delivers a powerful punch of neurotoxins which, in rare cases, can kill a human.
And, while many scorpion venoms are dangerous, scientists have also been investigating their therapeutic potential. A recent paper published in PLOS ONE suggests that the venom of the Pakastani yellow scorpion has anticancer and anti-inflammatory properties.
3. They Boast Multiple “Defensive” Systems
For their size, scorpions are about as close to an “indestructible” organism as you will find. They sting with their tail, which has 360 degree motion. Their two front pincers can be used to attack prey and fend off predators. They can live for up to a year without food. And, although they tend to reside in arid climates, the structure of their lungs allows them to survive submerged in water for over a day.
It’s also worth reiterating: they can survive an atom bomb explosion. Dorald Allred, lead author of this research, writes, “Fifty-three arthropod species were studied in an area affected by an underground nuclear detonation. […] One and two months after the detonation, the number of species was reduced from the expected by 48 percent, by 52 percent after 11 months, and by 66 percent after 13 months. The greatest reduction of specimens occurred with spiders, followed by ants and beetles. Fewest changes occurred in the number of scorpions.”
4. They Care For Their Young
Unlike spiders and other arachnids which lay eggs, scorpions give live birth. After birthing her offspring, a mother scorpion will carry her babies around on her back, protecting them until they are able to hunt on their own.
But don’t get the idea that scorpions are warm and cuddly creatures. If the mother gets too hungry, she will resort to eating her babies.
In addition to parental care, females of some scorpion species can reproduce without the need for mating, using a type of asexual reproduction known as parthenogenesis.
5. They Are Ecologically Diverse
In addition to occupying many regions of the globe, scorpions have evolved ecologically into a variety of different habitat specialists within the ecosystems they inhabit.
Recent research has characterized scorpions into four types of habitat specialists: vegetation dwellers, rock climbers, hard soil burrowers and sand burrowers. Their physical traits even reflects these different ecologies, indicative of adaptation to their environment. For instance, species with longer walking legs tend to be associated with sand burrowing or living in rock crevices.
Overall, scorpions’ evolutionary success can be attributed to their remarkable adaptability. Over millions of years, their ability to thrive in diverse habitats have solidified their status as resilient survivors in the animal kingdom.