Processionary Caterpillars in Spain: A Dangerous Threat to Animals and Children

by Lorraine Williamson
dangerous processionary caterpillars

Spain is known for its beautiful forests and natural landscapes, but these places also host a danger that many people are unaware of: processionary caterpillars. These small creatures, also known as pine processionary caterpillars, are common in Spain and are particularly dangerous to animals and children.

The Policia Nacional has issued a warning reminder on their social media, emphasising the importance of being cautious and alert during the caterpillar season.

What are processionary caterpillars?

Processionary caterpillars are the larvae of a species of moth called Thaumetopoea pityocampa. These caterpillars are covered in tiny hairs that contain a toxin called thaumetopoein. They are called processionary caterpillars because they move in a long line, or procession, in search of food. They are commonly found in pine forests, where they feed on the needles of pine trees.

The dangers associated with processionary caterpillars

The main danger associated with processionary caterpillars is their toxic hairs. These hairs can cause severe allergic reactions in humans and animals. In fact, the toxicity of these caterpillars is so high that even being in close proximity to them can cause a reaction. The hairs can cause itching, rash, and even respiratory problems if they are inhaled.

The danger to animals

Animals are particularly vulnerable to the dangers of processionary caterpillars. Dogs are often attracted to the caterpillars, and if they come into contact with them, they can suffer from severe allergic reactions. In some cases, this can lead to amputation of their tongue, or even death. The Policia Nacional is therefore, warning dog owners to be particularly careful when walking their pets during the caterpillar season. This does not only apply to pine forests as pine trees are also common in urbanisations. Moreover, the caterpillars can travel quite far.

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The danger to children

Children are also at risk from processionary caterpillars. They may be curious about the caterpillars and try to touch them, which can lead to severe allergic reactions. In some cases, the reactions can be so severe that hospitalisation is required.

Preventing contact with processionary caterpillars

Preventing contact with processionary caterpillars is the best way to avoid the dangers associated with them. If you are walking your dog in a pine forest, keep them on a leash and be aware of the caterpillars. However, if you see them, keep your distance and avoid letting your dog investigate them. Furthermore, teach your children to stay away from the caterpillars and to never touch them.


If you see cocoons in a pine tree, it is important to avoid them and seek professional help for their removal. Touching the cocoons can cause the caterpillars to fall out and come into contact with people or animals, leading to severe allergic reactions.

dangerous processionary caterpillars cocoon

Also read: More information on these dangerous processionary caterpillars

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