Mallorca lizards: AI spots newcomers by belly scales

On Illot d'en Curt, Mallorca, 4,619 lizard photos help an AI tool tell familiar animals from newcomers by the scales on their bellies. Researchers at the Mediterranean Institute for Advanced Studies (Imedea) reported the results on 8 October 2026. The tool, called ReMatch, is designed to identify individual Balearic lizards, known locally as sargantanes.

A match in the scales

Each lizard has a distinctive pattern of belly scales. ReMatch looks for matching points and lines between a new photo and images in its database. If no match is reliable enough, it can flag the lizard as one not yet recorded.

When a lizard was already in the database, ReMatch put the right animal first in 98.4% of cases. In a test that also included unrecorded lizards, it was correct 92.46% of the time. The researchers used 4,619 photos of 1,009 lizards taken during fieldwork from October 2010 to September 2024.

Following lizards without tags

Recognising the same lizard over time helps researchers see which animals reappear and which are no longer observed. Photos offer an alternative to rings and tags, which can require animals to be caught and handled. The image collection is now openly available.

ReMatch has limits. Lead researcher Roberto Alcaraz said large changes in camera angle or image conditions make it less effective. It also performed well on zebra stripes, seal fur and human fingerprints, but less well on whale sharks.

Topics: Nature & wildlife

Source: Europa Press / Mallorca.com