Invasive Lizards Proliferate in Argentina, Posing No Threat to Humans

Residents in La Plata, Argentina, and surrounding areas are increasingly noticing the presence of modest lizards, a phenomenon that is becoming more common throughout the region. While these reptiles are considered an invasive species, experts assure the public they pose no significant danger to people.

The Spread of Invasive Lizards

The lizards, first observed in the 1970s in what is now Puerto Madero, have rapidly colonized urban areas, spreading from Buenos Aires to Montevideo and beyond. Their arrival is believed to have occurred via shiploads, with multiple species entering Argentina over time. Sightings have expanded exponentially throughout vast metropolitan areas and other provinces.

Why are They So Successful?

The success of these lizards is attributed to their status as an invasive species. In their new habitat, they lack the natural predators that controlled their populations in their native environments. This, combined with a “highly high reproductive potential,” allows their numbers to grow quickly, particularly during warmer months. As reptiles, they are cold-blooded, meaning their metabolism and activity levels increase with temperature.

Species Identified

The predominant lizard in the region is the Mauritanian tarantola, measuring between 5 to 15 cm in length, plus a similar length for the tail. Males are typically larger and have larger heads than females. They primarily feed on insects but can also exhibit cannibalistic behavior, consuming their own offspring. Another species, Hemidactylus mabouia, native to West Africa and having invaded Brazil centuries ago, has also been found in the Iguazú area of Misiones and is spreading southward. It is described as somewhat “slenderer and pinker” than the more common gecko. Rarely, specimens of Hemidactylus turcicus have also been identified in the country.

Are They Dangerous?

Experts emphasize that these lizards are “absolutely harmless to people.” Bites are unlikely and would not pose a threat, occurring only if the lizard is directly handled. They can, however, contribute to environmental balance by consuming insects.

Defense Mechanism: Autotomy

These lizards possess a unique defense mechanism called autotomy, allowing them to self-cut and detach their tail when threatened. This distracts predators, enabling the lizard to escape.

Reproduction and Population Growth

The lizards lay small, spherical eggs with thin calcareous shells, typically producing only two or three offspring per clutch. However, with abundant food, they can have two clutches per season, contributing to their rapid population growth.

How to Discourage Their Presence

To limit the presence of these lizards, experts recommend reducing their shelter and food sources. This includes keeping walls clear of vines and crevices and periodically spraying with insecticide to control insect populations.