Scientists identify individual lizards by their irises

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.

Citations:

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

Wildlife drones could revolutionize aerial surveys of animal populations

(09/30/2013) In open areas, like the African savannah, scientists often estimate wildlife populations through manned aerial surveys. However a new study in mongabay.com’s open access journal argues that using small drones may be more cost-effective, safer, and capable of reaching more remote areas. Researchers tested the accuracy of drone counts in Bazinga Game Ranch (NGR) in Burkina Faso.

Google Earth presents fish-eye view of coral reefs

(08/20/2013) You can now visit up-close and personal some of the world’s most imperiled ecosystems on Google Earth: coral reefs. The Google team is working with scientists to provide 360 degree panoramas, similar to Google street-view, to give armchair ecologists a chance to experience the most biodiverse ecosystems under the waves.

New Android app helps you identify frogs in the Western Ghats

(08/15/2013) Amphibians hop onto your Android phone in an app that focuses on ease of use. There are many among us who have gone out for a walk in the night, during the rains, and heard frogs chorusing. Or looked upon a small amphibian perched perilously by the wayside, and wondered what it is called.

Near real-time deforestation monitoring system to go global

(07/25/2013) A near real-time deforestation monitoring system will soon cover all the world’s tropical forests, report the researchers behind the initiative.

Researchers produce the most accurate carbon map for an entire country

(07/22/2013) Researchers working in Panama have produced the most accurate carbon map for an entire country. Using satellite imagery and extremely high-resolution Light Detection and Ranging (LiDAR) data from airplane-based sensors, a team led by Greg Asner produced a detailed carbon map across the Central American country’s forests. The map reveals variations in forest carbon density resulting from elevation, slope, climate, vegetation type, and canopy coverage.

Scientists build app to automatically identify species based on their calls

(07/16/2013) New technology makes it possible to automatically identify species by their vocalizations. The platform, detailed in the current issue of the journal PeerJ, has been used at sites in Puerto Rico and Costa Rica to identify frogs, insects, birds, and monkeys. Many of the animals identified by the system are typically difficult to spot in their natural environment, but audio recordings of their calls reveal not only their presence but also their activity patterns.