Giant Birds: What is the rule of the island?
Islands can be intense natural laboratories for evolution. Relative isolation can cause organisms to adapt very differently from those found on the vast expanses of Earth’s continents. According to a phenomenon called the rule of the islandFor example, large species tend to grow smaller to survive on more limited resources, while animals that are typically small (like rodents and lizards) grow to unprecedented sizes.
When first described in 2010, the Flores stork was thought to be part of this pattern. The bird was originally imagined as a unique, flightless giant that had adapted to stalk smaller prey in the island’s forests. However, revealing that The stork of Flores could flyit is suggested that it was probably not a case of island evolution, but was part of a family of giant storks that once flew over much of the world.
“I think my perception of L. robustus It changed a lot during my career,” says Meijer, who studied some of the earliest specimens of the giant bird. The original set of bones, he said, were large and strange, and seemed to fit the idea that island life changes creatures in unexpected ways.
But the discovery of the animal’s wing bones presented a different picture.
What the study says about the flight of giant birds
Liang Bua Cave preserves a treasure trove of paleontological and archaeological specimens, including remains of Homo floresiensis there Homo sapiensstone tools used by both species and a collection of animal bones.
The first bones of L. robustus they were discovered in 2004, but it took experts many years to collect and catalog more animal remains. It was only after the new study that Meijer and his colleagues put all the pieces together to paint a more complete picture of the animal.
If the Flores stork had not flown, the bird’s wing bones would have been smaller and would have shown anatomical signs indicating that they were no longer used for flight. Paleontologists have seen it time and time again among extinct carnivorous “terror birds”, emus and their relatives, and various other land species that evolved after the extinction of dinosaurs 66 million years ago.
When the stork wing bones from Flores were identified in the Liang Bua Cave collection, Meijer recounts, “they looked like functional wing bones and nothing like those of flightless speciesThese discoveries inspired Meijer and his colleagues to rethink the life of the giant bird.
“You think about how they would have behaved and interacted with the other species on Liang Bua,” he muses, “almost like you were getting to know an animal on a personal level.” Each skeletal piece recovered from the cave is another part of the puzzle.
The new analysis “demonstrates that our understanding of the fossil record is constantly improving, and that our initial interpretations of the anatomy and behavior of a fossil animal are preliminary hypotheses subject to re-evaluation”, concludes the paleontologist from the University of Cambridge, Daniel Field, who was not involved in the study. These revisions not only help paleontologists better understand how and why species evolved, but also provide new information about an organism’s extinction.
Looking at the distribution of giant storks in prehistoric Africa and Eurasia, for example, research also reveals that L. robustus it may have been one of the last surviving species of these once abundant birds. Clinging to an island refuge between the Indian and Pacific oceans, the giant birds eventually disappeared, but left clues to their history on the floor of Liang Bua Cave.