An Island Adrift
The story of Sardinia's unique animal life begins with a dramatic geological event. Around 30 million years ago, during the Oligocene, the landmass known as the Sardo-Corsican microplate was attached to what is now southern France and northern Spain. Tectonic forces caused this block of crust to break away and begin a slow, 90-degree counter-clockwise rotation into the Mediterranean. This continental divorce, which concluded around 15 million years ago, trapped a sample of European fauna on the newly formed island. This long period of isolation, with no land bridges to the mainland, led to a distinct evolutionary path. The animals marooned on this "ark" adapted to the island's specific conditions, free from mainland predators and competitors.
This isolation is the engine of "island evolution," a process that produced some remarkable creatures. On islands, evolutionary pressures can lead to gigantism in small animals and dwarfism in large ones. Sardinia is an example. Over millions of years, the island became a bestiary of endemic species found nowhere else on Earth.
Ghosts of the Pleistocene
For much of the Pleistocene epoch, Sardinia's fauna was dominated by creatures that now seem fantastical. One of the most common was the Sardinian pika (Prolagus sardus), a tailless lagomorph distantly related to modern pikas. Though called a giant rabbit, it was a different kind of animal entirely. It was an example of insular gigantism; while its mainland ancestors were small, Prolagus sardus grew to weigh over 500 grams, significantly larger than any living pika. Fossil bone beds show it existed in extremely high densities across the island.
The island's large mammals evolved in the opposite direction. The Sardinian dwarf mammoth (Mammuthus lamarmorai), descended from the much larger steppe mammoth (Mammuthus trogontherii), stood only about 1.4 meters tall at the shoulder. This is a dramatic size reduction compared to its ancestor. Another example of insular dwarfism was a species of deer, Praemegaceros cazioti. Slightly larger than a modern fallow deer, it was a fraction of the size of its giant deer relatives on the mainland.
The island's top predator was the Sardinian dhole (Cynotherium sardous), a small, endemic canid adapted for hunting the island's small, quick prey like the pika. Other extinct endemics included a giant otter (Megalenhydris barbaricina) that likely fed on shellfish. Most of this unique megafauna, including the pika and the dwarf mammoth, disappeared after humans began to settle the island, introducing new competitors and predators like dogs, rabbits, and foxes.
The Survivors
While the most unusual species are gone, Sardinia still hosts a number of endemic vertebrates. The Sardinian red deer (Cervus elaphus corsicanus), a distinct subspecies, was saved from extinction in the 20th century. By the 1970s, only a few hundred individuals remained, but conservation and reintroduction programs have helped the population recover to several thousand.
Sardinia is a hotspot for amphibians, with several species of cave salamander from the genus Speleomantes (also called Hydromantes). These creatures, such as the brown cave salamander (Speleomantes genei), are Europe's only lungless salamanders, breathing entirely through their skin. This requires cool, moist environments, which they find in the island's numerous caves and rocky forests. The island is also home to endemic reptiles like Bedriaga's rock lizard (Archaeolacerta bedriagae) and the Tyrrhenian wall lizard (Podarcis tiliguerta).