Which creatures in your garden are actually dangerous, and which just look it? This is an A–Z of the bugs and small animals gardeners most often worry about, with a straight answer on each.
A note on wording: most of these are venomous rather than poisonous. Venomous means it injects a toxin (a bite or sting); poisonous means it is harmful if you eat it. It matters, because it changes what to do about it.
Jump to a creature
Centipedes · Cicadas · Garden Spider · Ladybugs · Millipedes · Monarch Butterfly · Salamander · Skinks · Slugs
Centipedes
Centipedes are poisonous. They have maxillipeds, which are a special pair of front legs that can wrap around their mandibles and inject venom into a person or an animal. When they catch their prey, they release poison from a gland below their fangs. Although their venom is poisonous, it isn’t normally life-threatening for people.
Cicadas
Cicadas are non-toxic and safe for humans and animals. People who are pregnant or lactating, have shellfish allergies, or have gout should avoid consuming cicadas. Animals should not consume cicadas in large quantities as their exoskeletons can cause intestinal issues, including vomiting and diarrhea.
Garden Spider
Garden spiders are poisonous. However, a more precise term to use is venomous, as the garden spider injects venom into its prey in an effort to paralyze it. Paralysis usually occurs in smaller prey such as insects. However, humans and other animals react to the venom differently.
Ladybugs
Ladybugs are not poisonous to humans. That said, they do have some ability to poison small animals, such as lizards and birds. When they are threatened, they release a foul scent that lets other animals know that they can defend themselves. They have special glands in their feet that release pyrazine, and their bright colors warn predators that they aren’t good to eat.
Millipedes
Unlike centipedes, millipedes are not poisonous. However, there are species that have glands that produce fluids that can trigger an allergic reaction in some people. These fluids contain hydrochloric acid, which can damage the skin. It can also harm your eyes. You should wash your hands with soap and water and use alcohol if you come in contact with their fluid.
Monarch Butterfly
Monarch butterflies are poisonous. Their poison isn’t potent enough to harm humans, but they can make their predators sick, including frogs, grasshoppers, lizards, mice, and birds. Their bright colors do warm these critters that they are dangerous. The Monarch absorbs the poison and stores it when it is a caterpillar and eats the milkweed plant. This is the only place they will lay their eggs.
Salamander
While salamanders can have bright colors, their bite is not poisonous to people. However, their skin is poisonous, so you should always wash your hands and avoid touching your mouth or your eyes if you touch one. They secrete this substance from the glands in their skin, and it can cause irritation. They are harmless if you don’t touch them.
Skinks
Skinks are not poisonous to people. In fact, not one skink breed is poisonous. They can bite, although it is uncommon, and the bite doesn’t carry any venom. There are superstitions that skinks are poisonous because of their bright colors, but you don’t need to worry. They are usually a low-risk pet to have.
Slugs
Slugs are not poisonous, but they can be unsafe to people or animals who eat them. They often carry a parasite called the rat lungworm, which can cause nerve damage after traveling to the brain and spinal cord. They also produce a slimy mucus that can cause vomiting in pets, and they leave behind residue on plants in the vegetable garden.
Related
Poisonous plants A–Z — toxicity of 52 common garden plants to humans, dogs, cats and livestock.