When we think of Madrid, the capital, it’s very likely that the first thing that comes to mind isn’t exactly the richness of its local wildlife (the Bear and Strawberry Tree statue doesn’t count). However, perhaps the city can still surprise us with new—or rather, returning—residents. For example, otters.
On April 19, city surveillance cameras spotted an otter at Dam 6 on the Manzanares River, in the section between the Puente Oblicuo and the Andorra footbridge that marks the boundary between the Arganzuela and Latina districts. There had been signs before, such as footprints and remains of devoured fish. In addition, technicians found droppings—which otters use to mark their territory—and also used videos posted by citizens on social media to identify the animal.
This isn’t the first time an otter has been spotted in the waters of the Manzanares in recent years. As early as 2019, an otter was seen at the Puente de los Franceses; in 2020 at the Puerta de Hierro interchange; in 2022 at the Puente de Segovia; and in February of this year in El Pardo. That’s a lot of sightings for an animal that had been completely absent from the Manzanares River for 50 years.
The Renaturalization of the Manzanares River
The otter is an endangered species in the Community of Madrid, and its presence is often considered a bioindicator—that is, a sign of the good environmental health of rivers and wetlands. It is not the only species that has returned to the Manzanares; birds, reptiles, small mammals, and fish that had also disappeared for decades have been gradually reappearing or being reintroduced into the river.
Over the past two years, protected fish species—such as bogas, bermejuelas, colmillejas, and cacho—which inhabited the river until the middle of the last century, have been released into its waters. In addition, viperine snakes, voles, hedgehogs, field mice, and even foxes, among others, have also reappeared around the Manzanares.
The initiative regarding the river’s wildlife is part of a broader strategy of actions aimed at restoring the Manzanares. Among the measures implemented by municipal services to protect native species are the restoration of the riparian forest, the improvement of water quality through waste removal, and the control of invasive species.
Measures to renaturalize the Manzanares began in 2016, spearheaded by the Madrid City Council and the Ecologistas en Acción confederation. The goal was to restore the river’s natural course, and to that end, in May of that same year, all the dams along its 7.5-kilometer urban stretch were opened. Now there appear to be increasingly visible signs of improving water quality, such as the presence of small otters swarming in the riverbed.