Evolutionary Characteristic Allowed Penguins to Adapt to Cold Climate
22.12.2010 - Flora & Fauna, Antarctic
Modern penguins, which live in the extreme conditions of Antarctica, may have evolved a way to retain heat while they were still living warm climates in the past, researcher Daniel Thomas of the University of Cape Town and his colleagues have discovered. According to a research paper published in Biology Letters, this adaptation has helped modern penguins conquer Antarctica over the course of the past 16 million years.
The key adaptation penguins developed is the humeral arterial plexus, a network of blood vessels that limits heat loss through the wings. The plexus routes blood coming into the body from the wings past the blood traveling from the body to the wings, which allows warm blood travelling from the body to heat cooler blood from the wings returning to the body, making it possible to conserve heat.
In determine how this anatomical structure evolved, a team of scientists conducted studies on seven live penguin species and 19 fossil species. In the live specimens, the scientists found the plexus leaves behind grooves in the humerus, which enabled them to trace the origins of the change in the fossil record. They were surprised to find that the earliest-known penguins to feature the plexus lived about 49 million years ago, on what is now Seymour Island in Antarctica.
The researchers believe the plexus was an evolution to help penguins save energy on long trips in the cold water. Apparently, the structure evolved along with dramatic skeletal changes that improved buoyancy and reduced drag, allowing for better deep-sea diving and long-distance swimming abilities. As the climate slowly cooled, the plexus had a new role, becoming instrumental to penguins’ survival in Antarctica.
