Fire Salamander - The Last Urban Dragon | Free Documentary Nature

Legend says there were creatures living in the depths of the earth that were born of fire and able to extinguish the flames when they walked over them because they were as cold as ice. Some even claim that they were the symbol of the damned because they could suffer the flames of hell without being consumed. It was said of them that they possessed a mortal poison capable of drying fountains and ruining fruit trees. They were considered so dangerous that according to Roman law, any man who provided another man with one of its parts would be condemned to death by throwing him to the beasts. Such was their power that legend says that 2,000 horses and 4,000 men of the armies of Alexander the Great died after drinking water from a river where one of them lived. Like dragons, during the Middle Ages they were thought to have magical powers, arousing fear and admiration in equal parts and revered as a symbol of purity. This magical creature, that even today continues surrounded by mystery, is none other than the fire salamander. Their habit of hiding among dry tree trunks probably first gave rise to the myth of their resistance to fire, since throwing firewood onto the fire would cause them to emerge from the flames as if by magic. The truth is that in this situation they would die quickly and their supposed powers would not prevent them from burning up. As for the terrible poison that salamanders use to poison rivers and springs, dry trees and bite a man and kill him in seconds, none of that is true. Salamanders, if they feel threatened, can secrete a substance that is toxic but virtually harmless to humans that deters many predators. The black and yellow color pattern of the salamander is common among many species and represents an alarm signal that tells potential predators that it is better to turn around and choose a harmless prey. Even our species uses that color code in signals to warn of possible danger that is best avoided. But despite toxins and warning coloration, fire salamanders may meet the end of their days as part of the menu of many animals, such as otters, birds of prey and even vipers. Salamanders are amphibians, like frogs, and also like them, their smooth, bare skin works as a respiratory organ, so it must constantly remain moist. Because of this, they prefer to hide during the day, coming out on rainy and temperate nights to return to their refuges at dawn. Newts are close relatives of salamanders and have an aquatic life for a few months a year. With the arrival of spring, they come to the ponds to breed, and when the eggs hatch, larvae remain in the water to complete the metamorphosis. Salamanders have managed to go a step further in their evolutionary path, and although they prefer damp and shady forests, they visit the water only once they have reached the adult stage. Not too long ago, most of the Iberian Peninsula was covered with woods, a perfect place for a forest amphibian. But with the growth of human population and natural climatic oscillations, many of these woods disappeared. And as the trees were being cut down to build towns and cities, men were invading the salamanders' natural habitat and creating barriers that restricted their movements. In 1928, the presence of salamanders on the banks of the old train station of El Vasco, in the city of Oviedo, called the attention of biologist José Bernárdez. Intrigued by their appearance, he picked up a few animals and sent them to Germany, where they were classified as a new subspecies named Salamandra salamandra bernardesi, in honor of their discoverer. From that moment, this subspecies, which occupies much of the Cantabrian area, was popularly known as La Salamandra de Oviedo, where most of its citizens hadn't even noticed the presence of this singular neighbor. The city of Oviedo was founded in the year 761 A.C., when the monks Máximo and Fromestano settled on the hill that is now the city's old town. There, King Fruela I ordered the construction of the early Church of San Salvador, which over the years would become the present cathedral. Later, Alfonso II moved the court to Oviedo, expanding it with several buildings, mainly ecclesiastical, and raising a defensive wall around it. The rapid growth of the city made necessary the construction of a second wall in the 13th century, under the reign of Alfonso X the Wise. These walls not only isolated the court and the clergy from the population outside the walls, but also locked inside salamanders, which ended up trapped between walls and cobbled streets. Twelve centuries after its founding, Oviedo has become a modern city where more than 200,000 people live, in which the asphalt and buildings have replaced the forests and meadows, leaving only a few green spots in some parks and private gardens. But how have the salamanders managed to survive in this environment, so different from the wet forests that they had adapted to over millions of years of evolution? In most of their distribution range, which occupies central, eastern and southern Europe, female salamanders give birth to their young in the water, where the young remain for several months until after the metamorphosis reabsorbs their gills and allows them to venture out onto the land. This form of reproduction has kept them linked to the water, at least during the first months of their life. But this salamander subspecies, along with a few others, including some Galician island populations, have a feature that differentiates them from other salamanders of the same species. They are able to give birth to live young that don't need to pass an aquatic phase. Viviparity has made Oviedo's salamanders independent of bodies of water and opened the doors to an environment in which other amphibians wouldn't have survived. From the moment they are born, small salamanders, miniature replicas of their parents, are able to survive on their own without care. But only a few, the strongest and luckiest, survive and can live up to 20 years. In the most unexpected places in the city, where citizens walk, play and work, these amphibians remain hidden until nightfall. After dark, and when most people return to their homes, they leave their day shelters and begin their journey. They prey on worms, snails and small invertebrates that, like them, take advantage of the darkness to come out of hiding. As cold-blooded animals with a very slow metabolism, a dinner like this may be enough to last several days. In the city, they have almost no enemies. Only cats can catch some of them from time to time, but usually don't eat them. There are few animals that have moved into our towns in search of a new home, and some of them are so linked to humans that they'd hardly be able to survive without us. Despite the noise and pollution, they were able to profit off of some of the advantages of city living, such as milder temperatures, few predators, shelter and abundant food. A good example of this are starlings, which in autumn and winter form huge flocks to go to sleep night after night in the city parks. Salamanders, however, have not voluntarily chosen to live among us. These animals were trapped in the city as it grew. Almost a century after José Bernárdez discovered them on the slopes of El Vasco, a group of scientists from the University of Viedo and Cibio, from the University of Porto, became interested in them. These researchers selected various locations within the city, from the old town to modern neighborhoods, where they collected samples for more than 300 individuals. Molecular genetics techniques were used for this research, and the results obtained were surprising. The growth of the city caused the isolation of some groups, leading to genetic differentiation among them, a phenomenon that has increased over time as the possibility of connecting naturally has disappeared. Not only that, some groups didn't exceed 15 breeding individuals. Over hundreds of years, and due to the small number of individuals who were isolated, much of the gene pool was being lost, favoring differentiation by genetic drift. This phenomenon is a random process that occurs through the loss or fixing of an allele, a different version of the same gene, when populations are isolated at a reproductive level. Therefore, genetic drift and natural selection have been the mechanisms that favored the evolution of these populations. Smaller populations, and those that had been enclosed within the ancient walls of the city, showed greater differentiation, separating into independent genetic groups, in some cases less than 100 meters away from each other. One of the most singular populations is found in the Monastery of San Pelayo, which has probably been isolated from the outside since it was founded by Alfonso II in the 9th century. Its outer walls have remained almost intact since its construction, even during the bombings that took place during the Revolution of 1934 and the Spanish Civil War. Salamanders from the Monastery of San Pelayo have become cloistered salamanders over the last few centuries. Wall to wall with the Monastery is Oviedo Cathedral, definitely the most recognizable and representative building of the city. This building is a mixture of architectural styles, from the pre-Romanesque of the Holy Chamber to its unique Gothic tower. The cathedral suffered the effects of the bombs, including the Holy Chamber, which was badly damaged after the explosion of a dynamite charge on October 11th, 1934. A break in the walls could allow the exchange of individuals with other neighboring populations and a return to isolation after the subsequent reconstruction, which finished at the end of 1942. When the sun goes down and the lights of the lampposts are lit, salamanders appear among the stones of the walls of the cathedral and among the tombstones of the pilgrims, as they have done since more than ten centuries ago. Despite their nocturnal and discreet behavior, the presence of salamanders was not lost on everyone. The artisans and stonemasons who carved the stones of the cathedral and whittled much of the furniture inside left evidence of them in their works, alongside representations of other animals, both real and imagined. It has been a long time since the first salamanders were trapped within the walls of Oviedo. During all those years, the city has lived historical events, witnessed the birth and death of many generations of Oviedo citizens, and seen kings, princes and celebrities walk the streets. And beyond all these events, hidden among the stones of the walls held in yards and gardens, salamanders have been constant inhabitants of the city and are likely to continue living among us if we leave them in peace. They have earned their certificate of residence in the city as some of its most illustrious citizens.