There is no organ that cannot be changed, there is no function that cannot be overturned. The forms we currently observe in living organisms are the result of intricate adaptive paths. For example, hair turned into leathery flakes. This is the case of the Pangolin, the only mammal in the world with a body covered almost entirely by scales.
Manis javanica (CR, Critically Endangered IUCN Red List) is one of the eight pangolin species currently existing, 4 of which are present in Asia and 4 in Africa. The term derives from the Malay word "peng-gulung", meaning "he who rolls up". If threatened, in fact, the pangolin closes itself up by balling up in its scaled armor. Overlaid like the leaves of an artichoke, the flakes are composed of keratin, a filamentous protein rich in sulfur, and grow for the entire life of the animal, such as hair and nails. Their edges are constantly filed, while the pangolin is busy digging burrows and tunnels in the ground. Devoid of teeth and with a long, sticky tongue, it feeds almost exclusively on ants and termites, consuming about 70 million a year.
It is bizarre to think that its most effective defensive strategy is today the 'made it the busiest animal in the world. Although trade in the eight pangolin species is banned internationally, around 200,000 pangolin are killed each year. Their scales are widely used in traditional Chinese medicine, for their alleged healing properties, while their meat is considered a delicacy in China and Vietnam.
After the outbreak of the Covid-19 pandemic, the pangolin was believed to be a possible key animal for the species leap of the Sars-CoV-2 virus from bat to man.