Institutions and governments have been scanning human irises for years to verify one’s identity—Google has been using this method since 2011—but could iris-scanning be employed on other species as well? According to a new study in Amphibia-Reptila, the answer is “yes.” Scientists have recently employed iris scanning to visually distinguish individuals of an imperiled gecko subspecies (Tarentola boettgeri bischoffi) found on Portugal’s Savage Islands off the coast of Western Sahara.
But why would you never need to tell wild geckos apart?
“Individual recognition of geckos (or any other animal) is of the outmost importance for the estimation of key population features such as population size, site fidelity and movement patterns that are essential for the development of effective conservation strategies,” explains lead author Ricardo Rocha to mongabay.com.
In fact telling geckos apart has been so important to conservation initiatives that scientists have already employed a number of strategies including marking individuals with paint or transponders. But the most commonly used method has been toe-clipping.
“[This is] a method where the first bone of certain digits is removed, according to a predetermined numbering code. Many species of geckos rely on toe pads that enable them to climb and therefore toe-clipping has been strongly criticized for being too intrusive and for possibly affecting the welfare and even survival of the marked animal,” says Rocha.
The stunning iris of a gecko from the Savage Islands, Tarentola boettgeri bischoffi. Photo by: Ricardo Rocha.
If effective, iris-scanning could be a much less intrusive way to tell geckos apart (the animals would still need to be caught for photos). Looking at nearly a thousands photos of Tarentola boettgeri bischoffi, researchers found they were able to tell individuals apart with a hundred percent accuracy. They then tested the gecko iris photos in an I3S (Interactive Individual Identification System) computer program. The program correctly identified individual geckos 95 percent of the time, and was much faster.
To date the iris identification has only been tried on Tarentola boettgeri bischoffi, but Rocha says the system could likely be used with other gecko species.
“It can also be applied to other geckos of the genus Tarentola and certainly to other species with similarly variegated iris pattern. We are currently testing the methodology for the identification of turnip-tailed geckos (Thecadactylus solimoensis), one of the world’s largest gecko species, native to the Amazon and so far we have been able to identify more than 20 individuals.”
Tarentola boettgeri bischoffi. Photo by: Luis Ferreira.
View of Selvagem Grande Island. Photo by: Luis Ferreira.
Tarentola boettgeri bischoffi. Photo by: Ricardo Rocha.
- Ricardo Rocha, Tiago Carrilho, Rui Rebelo. (2013) Iris photo-identification: A new methodology for the individual recognition of Tarentola geckos. Amphibia-Reptilia 34: 590-596
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