A layer cake of extinction
Għar Dalam is a 144-meter-long limestone cave that holds a complete history of Malta's prehistoric environment. The cave floor is a record, preserving distinct layers of sediment and bone that paleontologists can read. The lowest and oldest layers, some more than 500,000 years old, contain many fossilized bones from animals that lived here during the Pleistocene epoch. At this time, lower sea levels created a land bridge connecting Malta to Sicily, allowing European fauna to migrate south.
The most common remains belong to dwarf elephants and hippopotami. Trapped on the island when sea levels rose again, these large mammals underwent a process called insular dwarfism. Over generations, their size dramatically decreased to adapt to the limited resources. The smallest elephant species, Palaeoloxodon falconeri, stood less than a meter tall as an adult—the size of a large dog. Two species of dwarf hippo have also been identified from the bone deposits: Hippopotamus melitensis and the smaller Hippopotamus pentlandi. This bone-filled layer, sometimes called the "Hippopotamus Layer," is a thick breccia of skeletons washed into the cave over millennia. Above this is a layer containing remains of red deer, brown bears, wolves, and foxes, dating to around 18,000 years ago.
The first humans and a Victorian museum
The cave's topmost stratum is the "Cultural Layer," which contains the earliest evidence of human presence on Malta, dating back about 7,400 years. Neolithic people used the cave for shelter, leaving behind pottery, tools, and remains of the first domesticated animals brought to the islands. By the time humans arrived, the Pleistocene megafauna like the dwarf elephants and hippos were already extinct, likely due to climate change.
Italian paleontologist Arturo Issel was the first to formally investigate the cave for its prehistoric remains in 1865. His work, and subsequent excavations by figures like John H. Cooke and Joseph Baldacchino, unearthed the massive collection of bones that made the site famous. To display these finds, a museum was opened on-site in 1933. The main exhibit hall still retains its original Victorian-style display cases, with thousands of bones arranged by species in dense, decorative patterns. This style of presentation was meant to show visitors the sheer quantity of the discoveries. During World War II, the cave was repurposed as an air-raid shelter for the local population. Today, only the first 50 meters of the cave are accessible to the public, preserving the deeper sections for future research.