A recent study published in Royal Society Open Science questions the existence of an Ice Age giant bird, suggesting that previously cataloged fossils might simply be larger variations of modern common cranes.
In the nineteenth century, archaeologists investigating caves and swamps in Europe found a vast collection of remains from the ancient Ice Age. Among these findings, the French biologist Alphonse Milne-Edwards described an ancestral species of crane, named Grus primigenia, based on bone fragments taken from a cave in southern France.
Due to the notably larger size of its bones compared to contemporary cranes, the scientific community spent over one hundred and fifty years believing it was a distinct species that inhabited the end of the last Glacial Period, more than twenty thousand years ago.
However, new research, conducted in collaboration with the Centre for Paleogenetics in Stockholm, Sweden, and led by Bournemouth University, reached this conclusion after analyzing ancient DNA samples. The analysis was performed on 18 crane bones collected in England, Wales, France, Germany, and the Balearic Islands.
John Stewart, the article's author, expressed suspicion that these large cranes were, in fact, common European cranes of increased size. He speculates that the classification error might be linked to the size differences between males and females; the ancient males were larger than current birds, while the females of that period had a size similar to modern males.
The methods historically used contributed to this confusion, as previous studies classified these large birds solely based on the shape and size of their bones. With the advancement of genetic sequencing techniques, DNA analysis can now provide a much more accurate determination of these animals' identity.
Stewart also raised possible reasons why modern cranes are smaller. Hypotheses include selective pressures imposed by human activities on the habitats of these birds. Environmental changes could result in lower food availability or force migrations to areas with less resource competition. In times of scarcity, smaller individuals, which require fewer supplies, may gain an advantage.
The researcher emphasizes, however, that further investigation is needed to fully understand this issue. According to him, although many bird species are currently vulnerable to human intervention, it is plausible that the number of past extinctions has been exaggerated, given that some of these cases may only represent changes in the size of species that still exist.
Currently, the common crane can be found in much of Northern Europe, including Norway, Sweden, and Finland, as well as the western part of Asia. Characterized by long legs and necks, gray plumage, and a distinctive red mark on the head, they are known for flying in large groups organized in a V-formation during their migratory journeys.