In recent days, the Manzanares River has once again made headlines in Madrid . Persistent rains have caused its flow to increase dramatically, creating an unusual sight for many residents of the capital: an otter gliding calmly through its waters right in the heart of the city, particularly in the El Pardo area.
The sighting, captured on video and shared on social media, has attracted attention not only because of the striking sight of this mammal in a historically degraded river, but also because it confirms that the otter is once again appearing in the Manzanares River after decades in which it was considered extinct in the Community of Madrid.
A sighting that confirms the return of the otter to the Manzanares River.
The most recent scene shows an otter swimming in a section of the Manzanares River after the flooding caused by an intense rainstorm in early February. The animal appears briefly, submerges, reappears, and then disappears again into the river's brown waters, to the surprise of those in the area.
The video was shared by the environmental platform Jarama Vivo on their X profile (formerly Twitter). Accompanying the images, the organization emphasized the ecological importance of these scenes, noting that "river dynamics are necessary to improve rivers and the biodiversity associated with their channels and banks." In other words, floods and natural river processes, far from being just a problem, play a key role in ecosystem recovery.
A more colloquial tone has also crept into the online conversation. One user summed up the feelings of many by commenting that when a river is respected and cared for, nature usually responds . Behind that seemingly spontaneous phrase lies precisely the scientific explanation for the otter's return to the Manzanares River.
This is not an isolated case: in recent years, tracks, droppings, and other signs of this mammal's presence have been recorded at various points along the river, although direct sightings remained rare. Seeing an otter on video again in the middle of an urban environment confirms that the recovery process is on the right track, although there is still a long way to go.
From being considered “extinct” to starring in a new image of the river
For decades, the otter was considered virtually extinct in Madrid . The species was even thought to be extinct in the region for some 40 or 50 years, driven out of its rivers and reservoirs by chronic pollution, spills, dam construction, and the general deterioration of the river habitat.
The Manzanares River, in particular, became a symbol of environmental degradation and low biodiversity . International research even placed it among the European rivers most affected by pharmaceutical pollution, and for a long time it barely harbored any fauna sensitive to water quality.
In that context, the sighting of an otter in June 2019 marked a true turning point . That particular otter was spotted near the Puente de los Franceses (French Bridge), next to the then Vicente Calderón stadium, and was documented thanks to Francisco José García, a biologist from the Complutense University of Madrid, who managed to film the otter right in the urban riverbed.
That 2019 sighting was interpreted as a milestone: after nearly half a century without any records in that area, it was confirmed that the animal was beginning to return to the river. Specialists had already detected previous signs—traces, footprints, and droppings—but that first recording provided visual confirmation of its return to the Madrid section of the Manzanares River.
Since then, there have been other isolated incidents. In March of recent years, also coinciding with rainstorms and high water levels, some passersby claimed to have seen otters in different sections of the river. However, their presence remains very sporadic , and each new video or photograph continues to be considered a significant event.
The renaturalization of the river: works, investment and change of approach
The return of the otter cannot be understood without considering the transformation the Manzanares River has undergone since the mid-2010s . In 2016, the environmental group Ecologistas en Acción (Ecologists in Action) presented a project to halt the deterioration of the urban riverbed and promote its renaturalization, that is, to restore some of its natural dynamics and structure.
That proposal was adopted by the Madrid City Council, which allocated around 1,2 million euros to various projects to revitalize the river. One of the most significant measures was the opening of the dam gates that had kept the Manzanares River practically confined and with stagnant water as it flowed through the city.
By removing these obstacles, the riverbed began to reshape itself more freely: islands and meanders formed, the banks diversified, and riparian vegetation expanded . Along with reduced discharges and improved wastewater treatment, these interventions allowed the Tagus River Basin Authority to significantly improve water quality.
That improvement brought with it the return de pecesReptiles, amphibians, small mammals, and a greater presence of birds, many of them especially sensitive to the river's condition, gradually transformed the Manzanares River from a mere channeled infrastructure into a vital ecosystem. riverine area with ecological value in the heart of the city.
Ecologists in Action themselves have emphasized in recent years that the renaturalization of the urban stretch has helped Madrid's residents begin to value riverside environments as a socio-environmental opportunity . Walking along the riverbank is no longer just strolling past concrete, but approaching a green corridor where it's not uncommon to encounter herons, cormorants, or, with a bit of luck, an otter.
The otter as an ecological indicator of river health
The European otter is a semi-aquatic carnivorous mammal with an elongated body, short legs, and excellent swimming abilities. Its diet consists mainly of fish, although it also consumes amphibians, crustaceans, and small vertebrates, placing it as an apex predator in river ecosystems.
For this reason, its presence is usually associated with rivers that have a good food supply, riverside shelters, and acceptable water quality . It is not a species that tolerates intense and continuous pollution well, nor the disappearance of riparian vegetation, which it uses for hiding and breeding.
In the Community of Madrid, otters are native and their population remains relatively stable in more natural areas, especially in the Upper Manzanares River Basin Regional Park and along waterways such as the Samburiel, Recuenco, Santillana, and Chozas rivers. However, seeing them in the city itself is still very rare.
With their discreet and largely nocturnal habits, they are rarely seen in highly urbanized areas . Therefore, each sighting in the urban stretch of the Manzanares River takes on special significance, both scientifically and symbolically: it indicates that the river has improved enough for such a demanding animal to use it again, even if only occasionally.
Experts insist that these events should not be interpreted as the immediate consolidation of a stable population within the city, but rather as a positive sign of the river's ecological trajectory. Even with pollution problems and human pressures, the Manzanares River today bears little resemblance to the severely degraded riverbed of a few decades ago.
The role of floods and storms in wildlife movements
The meteorological context of these sightings is not accidental. The heavy rains of recent weeks have caused the Manzanares River to swell , increasing its flow and carrying sediment that connects sections of the river which, under low water conditions, remain more isolated from each other.
In this scenario, animals like the otter can move more easily from better-preserved areas to urban sectors, exploring new territories or following abundant prey. Ecologists point out that natural river dynamics —with episodes of controlled flooding—are fundamental to maintaining the structure and biological diversity of rivers.
The less pleasant side of these storms is that, while they facilitate wildlife movement, they increase the risk of flooding in other parts of the basin. The Tagus River Basin Authority has had to activate flood alerts on several occasions for rivers such as the Jarama, the Henares, and the Alberche, with sections exceeding safety thresholds and triggering emergency protocols.
In the specific case of the Manzanares River as it flows through Madrid, the recent floods have served as a reminder that an urban river is not just a water channel confined between walls, but a living system that responds to storms, expands, contracts, and reconfigures itself . And that, if given space and with reduced human pressure, it can once again support species that seemed beyond recovery.
The sight of an otter taking advantage of this increased flow has reignited the public debate about the river's true state: it is being discussed whether these sightings foreshadow a more stable presence of the species or whether, for now, they remain isolated movements favored by the current hydrological conditions.
The reappearance of the otter in the Manzanares River, with key sightings such as the one in 2019 near the former Vicente Calderón stadium and the recent images released by Jarama Vivo in the El Pardo area, has become one of the clearest symbols of the environmental recovery of a river that for years was synonymous with pollution . The combination of renaturalization projects, improved water quality, increased riparian vegetation, and flood events that connect previously isolated sections has allowed this demanding mammal to return, at least sporadically, to the heart of Madrid. There is still work to be done and problems persist, but the fact that a species once thought to be extinct is once again being seen in the Manzanares indicates that the changes made are not just theoretical: the river itself is beginning to show that, when given the opportunity to breathe, it is capable of recovering.