Cryptic Diversity Revealed: Iberian Peninsula Hosts Two Distinct Rabbit Species After Two Million Years of Separation

For over a century, the scientific consensus held that only a single rabbit species inhabited the Iberian Peninsula, at most separated into two regional variants. A new study published in Biological Conservation overturns that assumption.

Researchers from the Institute for Advanced Social Studies (IESA-CSIC), alongside colleagues in Portugal and the United Kingdom, have identified two species with independent evolutionary histories that have long been conflated under one name. The study, coordinated by Rafael Villafuerte and Miguel Delibes-Mateos with the TRAMAS research group, formally distinguishes the Iberian rabbit (Oryctolagus algirus) from the European rabbit (Oryctolagus cuniculus).

The Iberian rabbit occurs naturally in Portugal and western Spain, while the European rabbit dominates the eastern peninsula and is the source of populations introduced across Europe, Oceania, and the Americas, where it frequently becomes invasive.

{{image align=”center” size=”fullwidth” ratio=”auto” id=”4556139″ src=” url=” caption=”Distribution of the Iberian rabbit” alt=”Distribution of the Iberian rabbit” credit=”‘When taxonomy lags behind evolution'” copyrightlink=” naturalwidth=”2000″ naturalheight=”1089″ }}

The two lineages diverged approximately two million years ago when glacial cycles isolated them in separate refugia—one in the Ebro Valley, the other in the Gulf of Cádiz. Since then, they have exchanged genes only minimally, despite their superficial resemblance.

What sets them apart

The differences extend well beyond genetics. The Iberian rabbit is smaller, with darker fur, smaller litters, and earlier sexual maturity than its European counterpart.

They also differ in gut microbiome composition, meat quality, and the parasite communities they host. As Villafuerte notes, “the two species have always been there; what has changed is our knowledge of them.”

{{image align=”center” size=”fullwidth” ratio=”auto” id=”4556140″ src=” url=” caption=”Photographs of the Iberian rabbit (top), ” Oryctolagus=”” algirus=”” and=”” the=”” European=”” rabbit=”” (bottom)=”” cuniculus=”” alt=”Photographs of the Iberian rabbit (top), ” credit=”Fotografías de Daniel Burón y Marco Escudero – ‘When taxonomy lags behind evolution'” copyrightlink=” naturalwidth=”1406″ naturalheight=”2000″ }}

The authors draw parallels to recent taxonomic revisions in giraffes—once considered a single species, now recognized as four—and African elephants, now separated into savannah and forest species.

Why the discovery matters

The conservation implications are urgent. While European rabbit populations remain stable or are increasing across much of their range—even causing agricultural damage in some areas—the Iberian rabbit is in marked decline across Portugal and southwestern Spain. Managing both as a single species has obscured the severity of this collapse.

The problem is not merely statistical. Game restocking programs routinely release European rabbits—which are more abundant and prolific—into areas historically occupied solely by the Iberian rabbit. This practice accelerates replacement through competition and hybridization, Delibes-Mateos warns: “We cannot go on managing as a single species two rabbits that have evolved separately for almost two million years.”

The stakes extend far beyond the rabbits themselves. The rabbit serves as prey for up to 40 predator species, including the critically endangered Iberian lynx and Spanish imperial eagle, meaning its conservation status shapes the fate of much of Mediterranean wildlife.

Formal recognition of the two species would, the authors argue, enable tailored monitoring programs, recovery plans, and hunting regulations designed for each lineage—rather than applying criteria devised for only one.

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