Dominant Green Hulk Lizards Erase Millions of Years of Evolutionary Color Diversity

Lund University researchers report the aggressive Hulk lizard is wiping out yellow and orange wall lizard morphs, ending millions of years of color diversity.

By: AXL Media

Published: Apr 27, 2026, 6:45 AM EDT

Source: Information for this report was sourced from ScienceDaily

The Rapid Collapse of Ancient Color Morphs

A long standing biological equilibrium within the Mediterranean common wall lizard population is currently undergoing a swift and dramatic transformation. For millions of years, the species maintained a diverse array of three distinct color types, each representing a different survival and reproductive strategy. However, according to a study published in Science, this ancient diversity is being systematically erased by the rise of a highly dominant green variant. Researchers have observed that as this aggressive group expands, the previously stable coexistence of multiple color forms is failing at an unprecedented rate.

Large Scale Analysis of Mediterranean Populations

To track this evolutionary shift, a team of scientists led by Lund University examined more than 10,000 individual lizards across roughly 240 distinct populations. The data indicates that the "Hulk" lizards, distinguished by their larger size and striking green appearance, are fundamentally altering the social and competitive landscape of the species. Professor Tobias Uller, an evolutionary biologist at Lund University, explains that the emergence of this single dominant trait has disrupted the social systems that formerly allowed different survival strategies to function side by side.

The Vanishing Yellow and Orange Variants

The common wall lizard, or Podarcis muralis, has historically been characterized by white, yellow, or orange throat colors. These variants functioned as a stable evolutionary system where no single type gained a permanent advantage over the others. The recent research confirms that this balance is now a relic of the past in many regions. As the aggressive green morph moves into new territories, the yellow and orange variants are being eliminated, often leaving only the white morph as a surviving competitor in the wake of the green expansion.