Feral rabbits reveal new anatomical changes that defy expectations

In a groundbreaking study conducted in Australia, researchers led by Professor Sherratt analyzed the morphological differences of European rabbits, comparing their skull sizes and shapes across domesticated, feral, and wild populations. The research highlighted that when domesticated rabbits revert to a wild state, a process known as feralization, they do not merely revert to their wild form. Instead, feral rabbits were found to exhibit distinct anatomical changes that lie between wild and domesticated counterparts, showcasing overlapping features. This variation suggests that rabbit populations adapt traits to help them survive in varying environments, as demonstrated by their successful introduction into Australian ecosystems. The study also focused on how body size and skull shape variation resulted from numerous environmental factors, including the presence of large predators, which seems to be less of a concern in Australia. Although one might assume that feral rabbits would closely resemble their wild relatives, findings showed that feral rabbits have a morphology that is unpredictable and does not strictly follow a pattern of reverting to their ancestral form. This unpredictability indicates that feralization may be a unique evolutionary process rather than a simple recapitulation of previous forms. In their research, the team utilized recognized scientific methodologies to quantify shape and size variations in the skulls of rabbits, measuring domesticated, feral, and wild specimens globally. The results revealed a significant range of skull shape variations among domesticated rabbits, attributed to their extensive diversity in body size, contrasting with the more uniform skull shapes found in wild and feral rabbit populations. This contrast highlights a fundamental aspect of feral rabbit populations—they are adapting to their introduced surroundings while being influenced by both domestic and wild traits. Ultimately, the study aims to provide a deeper understanding of rabbit morphology and feralization processes. The researchers compared their findings to an extensive dataset of 24 rabbit species, allowing them to contextualize the morphological changes observed in domesticated, feral, and wild rabbits within an evolutionary framework. The study sheds light on the complexities of animal evolution and adaptation in response to changing environments, emphasizing that feralization is a multifaceted process shaped by ecological pressures rather than a straightforward reversion to ancestral forms.