A scorpion is the arachnid known for a venomous sting at the end of its tail. The tail is a segmented extension of the abdomen that curves forward over the body and ends in a bulb-like structure called the telson.
The telson contains the venom glands and the aculeus, the sharp stinger used to inject venom. Scorpions use their pincers to seize and crush prey, but the tail provides their primary weapon for subduing animals or deterring predators. Venom strength varies greatly among the more than 2,500 known scorpion species.
Scorpions are ancient arachnids. Fossil evidence shows that their lineage reaches back more than 400 million years, making them older than the earliest dinosaurs. They occur on every continent except Antarctica and are especially associated with deserts, although many species live in forests, grasslands, caves, or human structures.
A scorpion is not the only animal with a venomous sting, but it is the canonical arachnid answer to this wording. Spiders inject venom through fangs near the mouth, whereas scorpions deliver it from the end of the abdomen. Most scorpion stings cause localized pain, though some species can be medically dangerous.