Senda del Oso: Paca and Tola Are Gone, Only the Bear Molina Remains

In the Senda del Oso enclosure, between the concejos of Santo Adriano and Proaza, only one bear is left, Molina: Tola died in 2018 and Paca on 10 April 2025. Seeing her is down to luck, since she roams freely over several hectares of hillside and can spend an entire morning out of sight; a wild bear seen from the trail is unlikely.

Search for anything about the Senda del Oso and almost everything that comes up still talks about Paca and Tola in the present tense. Tola died in 2018 and Paca on 10 April 2025, so today the enclosure holds a single bear, Molina. It's worth telling the trail's story with up-to-date information, and clearing up along the way the question everyone types before going: whether you can actually see bears.

Paca and Tola are gone: the correction almost nobody has made

The story starts in 1989. Poachers killed their mother in Asturias, leaving two cubs barely five months old orphaned; they came into the care of the Fondo Asturiano para la Protección de los Animales Salvajes that June. They were named Paca and Tola. In 1996, by then adults with no way of fending for themselves in the wild, they were moved into an enclosure built for them on Monte Fernanchín, at the mouth of the Foz del Picarós, right on the boundary between the concejos — the Asturian equivalent of municipalities — of Santo Adriano and Proaza. That enclosure, more than four hectares of wooded hillside, is what gave the whole trail its popular name.

Tola died in 2018. Paca held on seven years longer and was put down on 10 April 2025 to spare her further suffering: she was around thirty-six, had lost her mobility, and had gone days without eating. For a Cantabrian brown bear that's a great age, well beyond what an animal usually lives in the wild, and her death closed a chapter that had run for almost three decades.

Since then only Molina is left, also heard called Molinera. She arrived at the enclosure after being rescued and, like Paca and Tola, can't be returned to the wild. She lives in the first enclosure, the one from 1996. Worth spelling out plainly, because it's a fact that expires: before going, the sensible thing is to check the current situation on the Fundación Oso de Asturias website, the people who actually look after the animals. We verified this before publishing and review it every season, but information about a thirty-year-old living creature doesn't age well in a piece of internet text.

The bears in the enclosure aren't the bears in the mountains

Here's the confusion that half the internet drags around, and it's worth clearing up. The bears in the enclosure are rescued individuals who, for one reason or another — being orphaned too young, being injured, having grown used to human presence — can't survive in the wild. They're under permanent care. They're not a representative sample of anything: they're individual cases the Foundation took in because the alternative was worse.

At the same time, and entirely separately, a wild population of Cantabrian brown bear lives in those same mountains. Same species, same territory, but the two things have nothing to do with each other. Free bears move through the range with a finely tuned instinct for avoiding people, and a paved greenway with hundreds of bikes passing through it every day is exactly the kind of place they steer clear of. That population's recovery over recent decades has been one of the peninsula's most solid conservation successes, and much of it comes down to simply having been left alone.

The second enclosure, built in 2008 on the other side of the trail, helps explain the kind of work done there. It's deliberately designed with no corners, so no animal can trap another, and it sets aside an area for rehabilitating wild individuals who need a spell in captivity before returning to the mountains. In other words: part of the facility exists precisely so that some bears stop being there.

Can you see bears on the trail? The honest answer

In the enclosure, yes, with luck. Molina roams freely over several hectares of hillside with trees, scrub and uneven ground, and she's under no obligation to come up to the fence. She can spend an entire morning out of sight. In winter her activity drops a lot. Turning up expecting to see a bear the way you'd look at a painting is the surest way to be disappointed, and a good part of the complaints that circulate about the visit come from exactly that. In some seasons the Foundation has run guided observation activities at set times; if that interests you, check with them directly, since it changes from year to year.

A wild bear seen from the trail is a different matter. It's unlikely. It happens — some people have had that luck, almost always at a great distance, early in the morning, with binoculars, scanning the slopes opposite — but it isn't something you plan for, it's a stroke of chance. Selling the Senda del Oso as a route where you see wild bears is simply false, and it also pushes people to behave badly when none shows up.

What you will see, without relying on luck, is a narrow limestone valley with sheer gorges, a river running alongside the whole way, vultures gliding over the ridgelines, and vegetation that turns spectacular in October. That much is guaranteed. The routes into the enclosure lie barely a kilometre from the Puente de Villamejín, in Proaza, and about eight hundred metres from the Buyera picnic area, so getting there on foot or by bike takes no effort at all.

Under your feet there's a coal train

The trail isn't a path invented for tourists: it's a dismantled railway line. In 1883 a mining railway opened to bring coal down from Quirós, from Santa Marina to Trubia, and a branch line was later added starting at Entrago, in Teverga, joining the main line at Caranga de Abajo. That's why the route forms a Y shape: two arms coming up from the south that meet and continue north as a single trunk.

The steam locomotives stopped running in 1963 and the rails were lifted; mining kept moving coal out by road until it wound down for good in 1995. Work to turn the trackbed into a greenway had begun in 1991, and the sections opened in stages: La Esgarrada, by Tuñón, through to Proaza in 1995; Proaza–Entrago in 1996, the same year Paca and Tola arrived; Caranga de Abajo–Valdemurio in 1999, and later the continuation towards Santa Marina. That timeline explains an oddity that throws a lot of people off: the trail has no clear start or end, because it was never conceived as a route, only as a freight line.

The tunnels are the best part of it, and also the source of a widely repeated mistake. There are quite a few, cut straight into the rock, several over a hundred metres long, some lit and some not. But the famous Túnel de Veneros, around 260 metres, which dozens of pages credit to the Senda del Oso, isn't on the Senda del Oso at all. It belongs to the greenway running from Oviedo to Fuso de la Reina, another old line connecting to the north that many cyclists string together with this one. The fact has been copied so many times that almost nobody checks it any more.

How to ride or walk it without regretting it halfway

It's practically flat, with an asphalt or concrete surface, and it's accessible enough for people with reduced mobility to cover, bar the odd limitation at road crossings. That makes it one of the most rewarding routes in the north for going with children or with anyone out of practice. The classic stretch, from Entrago to Tuñón, comes to around twenty kilometres: fourteen between Entrago and Proaza, six more from Proaza to Tuñón. Add the Quirós arm towards Valdemurio and Santa Marina, and the extension north towards Trubia, and the whole network runs well past thirty kilometres; some put the entire network at fifty.

The most common mistake is trying to do all of it. It's linear, not a loop: every kilometre you cover is a kilometre you have to retrace, unless you've arranged a car waiting at the other end. It works far better to pick one stretch, take it slowly, and spend the time saved dropping down to the river or climbing up to one of the villages perched above. It shines most on a bike, and the area has rental outfits, several offering pick-up at a different point from where you set off.

Two practical things. First, a torch or a head-lamp: inside some tunnels you go from full daylight to total darkness within three pedal strokes, and holding a phone while cycling isn't a solution. Second, the railings. In 2019 there were serious accidents from failed protective barriers; follow-up inspections found more than two hundred defects, and funds have since gone into repairing railings, surfacing and signage. It's far better than it was, but it's still a route on a rail platform with sheer drops to the river at some points, and it's no place to be checking your phone or letting kids range twenty metres ahead unsupervised.

How to behave at the enclosure

There's one rule that sums up nearly all the rest: don't feed the animals. Not fruit, not bread, not your leftover sandwich. It sounds like bureaucratic fussiness, and it isn't. A bear that associates people with food stops behaving like a bear; for individuals being rehabilitated for return to the wild, that lesson ruins their chances and condemns them to stay captive for life. Feeding an animal in the enclosure is, literally, closing the door on another one.

Second is noise. Shouting, whistling or clapping to get the bear to come out does the opposite of what works: it just sends her further up the hillside, and nobody in the group sees her. Watching is done in silence, from the designated points, with patience, and without climbing the fences. If drones come up, the answer is no; they disturb the wildlife, and in many protected areas they're banned outright.

And a third, less obvious one, that holds for the whole valley: if you come across signs of a wild bear at any point — tracks, droppings, a marked tree — the right thing is to carry on along the path and not go looking. The reason that population has recovered is that the animals have managed to keep their distance. The visit to the enclosure makes sense for exactly that reason: it lets you come face to face with a bear without needing to disturb one in the mountains.

Where this actually is

The Senda del Oso sits on the Trubia-Proaza-Teverga axis, in south-central Asturias, running up the Trubia river valley from the outskirts of Oviedo. From the capital it's around forty kilometres and a little under an hour by car. From the Nalón valley, on the other side, allow a bit over an hour, since you have to loop round through Oviedo or cross mountain-pass roads. It's a day trip, not an after-lunch stroll, and saying so plainly heads off setting out late and reaching the enclosure as the light fades.

The upside is the area holds more than one day's worth. A step from the trail is the Desfiladero de las Xanas, an extremely narrow gorge carved by water that ranks among Asturias's most striking short hikes. The Valdemurio reservoir sits on the Quirós arm. Proaza has the Casa del Oso, the Foundation's headquarters since 1996: three floors with an exhibition, an audiovisual room and a documentation centre, and the logical place to start if you want to understand what you're about to see. Teverga has the Colegiata de San Pedro and, further up, the Cueva Huerta.

And it's worth going in knowing what kind of place this is. These are valleys where mining has shut down, with villages that lost population and now get by partly because people pass through on this trail. Mealtimes follow the Asturian clock, and outside them it's hard to find a kitchen open; in low season, many places close on weekdays. Booking a table in the small villages isn't over-caution, it's just normal.