Ibiza didn’t have snakes at all until fairly recently. The horseshoe whip snake, native to mainland Spain, arrived roughly two decades ago, most likely hidden among the roots of imported olive trees, and it has since spread across an estimated 90% of the island.
The good news for visitors: it’s non-venomous and not considered a danger to humans. You’re unlikely to see one at all unless you’re out hiking through scrubland or rural areas, since it tends to keep well clear of people.
The bad news is for the island’s wildlife. The snakes prey heavily on the Ibiza wall lizard, a species found nowhere else on Earth, and several isolated populations on offshore islets have already disappeared entirely. Regional authorities now trap thousands of snakes a year as part of an ongoing control effort, alongside a captive-breeding program for the lizards. If you spot one while out walking, there’s no need to worry, just give it space and let it move on.