Most people use the words “poisonous” and “venomous” interchangeably, but there is a difference. Some potentially dangerous creatures might also surprise you.
Venomous Arthropods
Arthropods are insects, spiders, scorpions, centipedes, and other organisms with their skeletons on the outside and no backbone. Venomous arthropods deliver venom by stinging or biting.
- Spiders. In North America, only widow spiders (genus Latrodectus) and brown spiders (genus Loxosceles) are considered dangerously venomous to people.
- Scorpions. The only potentially lethal U.S. species is the Arizona Bark Scorpion, Centruroides sculpturatus, from the southwest U.S.
- Centipedes. These fast-moving predators have the first pair of legs modified into fangs to kill prey, but they bite in self-defense if molested.
- Wasps, bees, and ants. Social species like yellowjackets, hornets, paper wasps, and honeybees, are more apt to sting than solitary species.
- Caterpillars. Many caterpillars possess venomous spines or stinging hairs.
- Predatory true bugs. Assassin bugs, and aquatic bugs like giant water bugs and backswimmers, use their short, sharp proboscis to kill prey or bite in self-defense.
Poisonous Arthropods
These are insects and related organisms that are toxic if you bite them, though touching alone can sometimes result in pain or sensitivity.
- Blister Beetles. These non-descript beetles excrete a toxic liquid (cantharidin) from body joints if pinched or crushed. The chemical can raise blisters on skin, and be lethal if ingested.
- Fireflies. Fireflies are beetles that possess poisons similar to the toxins of toads.
- Bombardier Beetles. These beetles blast hot, acidic gas when grabbed.
- Millipedes. These slower-moving, vegetarian cousins of centipedes produce toxic substances, even cyanide, that can cause chemical burns on the skin.
- Caterpillars. The Monarch butterfly, and many other caterpillars, feed on toxic plants, then sequester those poisons for their own defense.
Avoid insects with bright, contrasting patterns like black and yellow, red, or orange, as these colors often advertise them as venomous or poisonous.