In front of the famous Balearic island of Ibiza, a new, unexpected image is emerging for travelers and nature lovers: Increasingly, horseshoe snakes, an invasive snake species from the Spanish mainland, are gliding over the sea from the main island to the idyllic, offshore mini-islands. This development is making Ibiza known not only for its beaches and clubs but also bringing a pressing conservation issue into the spotlight.

The most important things at a glance

• Researchers observed in April 2024 how a horseshoe snake swam the sea route to the island of Santa Eulària.
• The horseshoe snake is harmless to humans but poses an acute threat to the endemic Pityus wall lizard.
• The Balearic government reported over 4,400 captured invasive snakes in 2025 alone, more than 3,600 of which were on Ibiza.
• Strengthened control measures as well as protection and breeding programs for endangered lizards are planned for 2026.

Floating snakes change natural spaces.

The horseshoe snake (Hemorrhois hippocrepis...has nearly populated all of Ibiza in the last two decades and is now reportedly starting to spread to neighboring islands. The distance of about 400 meters to the island of Santa Eulària was filmed for the first time in April 2024 – a moment that dramatically shifts the boundaries of the existing island ecosystem. Researchers believe that growing food shortages on Ibiza are prompting individual snakes to seek new territories in the sea: the spectacular swimming distances are thus more a product of survival instinct than of deliberate action.

Unique lizards on the brink of extinction

The spread of snakes is catastrophic for the population of the Pityusan wall lizard: This lizard species exists only on Ibiza, Formentera, and a few surrounding islands. Their numbers have already drastically declined on several of these islands. Experts like Alexander Haas from the Leibniz Institute for the Analysis of Biodiversity Change warn that these lizards are "evolutionarily highly specialized lines," and their disappearance would be irretrievable. The uniqueness of these reptiles has prompted the Balearic government to take swift action: protection programs, increased trapping systems, and breeding in Barcelona Zoo have already been initiated.

What bathers should know

For vacationers, there is good news: the Horseshoe Snake is non-venomous, avoids humans, and poses little danger even when encountered in the water. However, the idea of sharing the Mediterranean with a swimming snake can feel unsettling. Biologists, however, clarify that incidents are extremely unlikely. Meanwhile, the task of authorities and organizations remains to limit the worst consequences for the local ecosystem through capture actions and monitoring.

Protective measures and outlook

In 2026, the Balearic government is intensifying its efforts with more personnel, expanded capture operations, and stricter controls on vulnerable island areas. In parallel, a conservation program will be expanded to secure and breed wall lizards in protected populations. The central question for the coming years remains: Is this effort sufficient to preserve the delicate balance in Ibiza's unique island environment? For active and nature-interested travelers, this presents an opportunity to directly experience a fragile habitat threatened by rapid changes – as long as this chance still exists.