Are Monarch Butterflies Poisonous?

Monarch butterflies are known for their migrations. They make their way south in the fall, traveling to California and Central Mexico. They try to get away from the cold weather. These butterflies only live six to eight months, so they never return once they migrate. They are beautiful with orange wings and black borders.

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.

Are Monarch Butterflies Poisonous to Humans?

The poison in Monarch butterflies is not harmful to humans, but it can give them an upset stomach if they eat it. Most people don’t eat Monarch butterflies or their caterpillars, so it is rarely a problem. Monarchs are migratory, and the adults of the second generation travel more than 3000 miles from the north to California or Mexico.

Monarchs lay their eggs on the milkweed plant, and the caterpillars eat the leaves of this plant. They ingest the toxins and store it, and it is still there when they transform into a Monarch. The caterpillars eat up to 20 leaves a day, and they store all of the toxins. The milkweed toxin can be lethal to human beings when it is eaten in large quantities, but it is unlikely that any humans will eat Monarchs.

Are Monarch Butterflies Poisonous to Dogs or Cats?

Dogs and cats are predators, and they love to chase insects and other animals that catch their attention. In the course of chasing a Monarch butterfly, a dog or cat can catch it and accidentally swallow it. If this happens, the Monarch is poisonous to dogs and to cats. They don’t have enough of the toxin to kill the dogs or cats, but they can make them sick.

It is unlikely that your dog or cat will eat more than one Monarch butterfly (or caterpillar), so the likely symptoms are nausea, vomiting, and diarrhea. If this happens, you should monitor your dog or cat. If your pet continues to feel sick after vomiting or having diarrhea, you need to call the vet. The dog or cat might have eaten more than one, and the number of butterflies will increase the amount of poison in its system.

Yellow and Black Monarch Butterfly on a Flower
Yay Yellow and Black Monarch Butterfly on a Flower

However, if you live in an area where milkweed is present, milkweed is toxic to cats and dogs. They are less likely to eat it than grazing animals, but you will want to make sure that they don’t have access to it.

Are Monarch Butterflies Poisonous to Livestock?

Although your livestock is unlikely to eat a Monarch butterfly or a caterpillar, the plant that the Monarch depends on for survival, milkweed, is severely toxic to horses, to cattle, to goats, and to chickens. The problem is that if you have Monarch butterflies, then there may be milkweed nearby.

It takes very little milkweed to cause illness in a horse. Sheep, cattle, and sometimes horses can die from grazing on it. This is especially true during the growing season. Animals love to eat the leaves, and they have the highest concentration of toxins. A sheep will die after eating between 30 and 100 grams of milkweed, and it only takes a few hours.

Milkweed causes cardiac failure in livestock, so it is critical to keep them away from it. They can suffer from difficulty breathing, elevated temperature, dilated pupils, spasms, respiratory paralysis, bloating, and more. Chickens can also suffer from poisoning. The milkweed plant will kill them, and it is poisonous to deer as well.

Are Monarch Butterflies Poisonous to Birds?

Monarch butterflies are poisonous to birds. If a bird eats one, it will throw up and learn not to eat it again. The bright colors help warm wild animals that they are poisonous. This is often enough to deter them from eating the Monarch.

Other wild animals, such as frogs, lizards, and others that eat butterflies, will get sick and possibly die if they ingest the butterfly. However, the bright coloring serves as a warning to them as well.

Is it Dangerous to Touch a Monarch Butterfly?

Although it would be dangerous to eat a Monarch butterfly or its caterpillar, it is not dangerous to touch them. They don’t sting or bite, and they are fairly docile. They have bright colors, and they are often used in the classroom.

The Monarch is a fairly sturdy butterfly because it has to be strong enough to migrate over 3000 miles. If it loses a few scales from being handled, it will not hurt the butterfly. Monarch butterflies are not toxic to hold or touch. They are only toxic to people if they eat them. The toxins from the milkweed plant are stored inside the butterfly.

It is not dangerous for people to touch the milkweed plant either, but they need to be sure to wash their hands after touching it. The toxins reside inside the white milky sap in the leaves, and if a person touches it and then puts their fingers in the mouth, they might get an upset stomach.

Are Monarch Butterflies Endangered?

In 2020, the number of Monarch butterflies was less than 2000, which is much smaller than the ten million or more that existed in the 1980s. The main reason is the use of pesticides and climate change, along with loss of habitat.

The monarch butterfly is dependent on the milkweed plant. It only lays its eggs there, and one monarch can lay 300 to 500 eggs each season. However, only one or two out of 100 eggs will mature to a Monarch butterfly. In addition, milkweed has been removed from a lot of places because it is so toxic to grazing animals. Farmers and governments are removing milkweed to make it safe for farm animals.