The most unpredictable moment in the encierro is not the start. It is not the turn at La Curva de Estafeta. It is the moment a bull separates from the herd. This lone animal, called a suelto, is disoriented, reactive, and no longer following the group instinct that keeps the encierro moving forward. For runners on the street, a suelto changes everything about how the next seconds unfold.
What Is a Suelto?
The word suelto translates loosely to loose or free. In the context of the encierro, it refers to a bull that has lost contact with the rest of the herd. While the other bulls continue forward along the 875-meter route, the suelto is left behind, alone on a street full of people.
As Ray Mouton writes in Pamplona (2002), if the bulls break out of the corral together they should run well, for their predisposition to stay together in a herd is greater than their instinct to attack. If they are separated, the bull that is alone will attack. That single observation captures the core danger. A bull in the herd is focused on following the group. A bull without its herd has no such anchor.
What Causes a Bull to Separate
Dennis Clancey identifies multiple causes, and they range from the physical to the behavioral.
It can be a number of things. It could be a bull distracted because someone’s touching it. It could just be that it’s one of the bulls within that herd that is most wily and just has desire to strike out because it feels as if its area is too confined.
Dennis Clancey, Founder of Encierro and member of La Unica Pena
Falls are among the most common causes. When a bull weighing over 500 kilograms loses traction on centuries-old cobblestones, the gap between it and the rest of the herd opens within seconds.
It only takes a little bit of time before a bull is separated if the other bulls don’t fall and continue to run at the same pace.
Dennis Clancey, Founder of Encierro and member of La Unica Pena
A bull can fall because of a turn, because of misreading where the barriers lie, or simply because of the surface itself. Tight turns like the transition from the Plaza Consistorial into Calle Mercaderes or La Curva de Estafeta are where falls happen most frequently.
Human interference is the other major cause. Touching a bull, whether intentionally or accidentally, can provoke it to stop, turn, or charge. When a bull turns around, it separates from the herd instantly. This is one of the most important rules of the encierro: do not touch the bulls.
Mouton recounts in Pamplona (2002) how a bull from the Pedro Romero ranch named Papelero broke from the corral first and had no contact with the herd during a 1993 encierro. Out front and alone, the bull swerved and gored a local runner just seconds into the run, then continued to lead the pack uphill on Santo Domingo while carrying the injured runner on its horn. Mouton observes that a bull that breaks from the corral first and has no contact with the herd can be as dangerous as one left behind.
What to Do When a Suelto Appears
Dennis is direct about this. The answer is not complicated.
The vast majority of mozos need to get the hell out of the way. That will give space to the pastore to be able to do his job.
Dennis Clancey, Founder of Encierro and member of La Unica Pena
The pastores are the professionals positioned along the route whose job is to keep the bulls moving forward. When a suelto occurs, they need clear space to work. The more runners crowding around the bull, the harder it becomes for the pastores to guide the animal back up the route.
The biggest mistake people make around a separated bull is to freeze and to stay in place. You need to take off running.
Dennis Clancey, Founder of Encierro and member of La Unica Pena
The second biggest mistake is trying to climb over the barrier. In that moment, with a group of people all pressing toward the same exit point, a runner trying to get a leg through the wooden planks becomes a slow, exposed target. Dennis’s guidance is unambiguous: stay on your feet and run as fast as you can in whatever direction takes you away from the lone bull.
Mouton describes this scene in Pamplona (2002): a solo bull or suelto, separated from the herd, begins to rampage. One runner correctly attempts to lure the bull toward the end of the route; several bystanders appear as oblivious to the danger as they were when they lost count of the drinks they consumed during the night. The tension between experienced runners who understand what is happening and inexperienced bystanders who do not is part of what makes a suelto so dangerous.
Why Crowding Makes It Worse
The instinct to stop and watch is natural. It is also precisely the wrong response. When people crowd around a separated bull, they create a wall of bodies that prevents the pastores from doing their work. Photos from past encierros, like those captured during the dramatic Miura encierro in 2019, show pastores physically holding crowds back just to give the animal enough room to move.
The bull itself becomes more agitated with more bodies around it. Without open space, it cannot orient toward the remainder of the route. It charges at movement instead of moving forward. Every additional person standing nearby extends the duration of the most dangerous moment in the encierro.
The Cleanup Steers
After the main herd passes, a second group of cabestros (steers) is released from a pen next to the corralillo. These are the cleanup animals. Their job is to run the full length of the course and collect any bull that has separated from the original pack. The steers know the route, they know the bulls, and their presence can help calm a suelto and guide it forward. Until the cleanup steers arrive, the pastores and a small number of experienced runners are the only ones managing the situation.
How Ganaderias Factor In
Not all herds are equally prone to separations. The ganaderia (ranch) providing the bulls for a given morning influences how tightly the herd runs. Some ranches produce bulls that stay resolutely together. Others produce animals that are more erratic and quicker to break formation. Experienced runners in Pamplona pay attention to which ranch is running each day, because it affects the probability of encountering a suelto.
Mat Dowsett notes in Encierro! (2003) that the famous Miura bulls stick together resolutely as a herd with great discipline but if separated will cause havoc. That reputation is part of why the Miura morning is consistently the most closely watched encierro of the fiesta.
Vocabulario
- Suelto (SWEL-toh): A bull that has separated from the herd during the encierro. The most dangerous and unpredictable situation on the route.
- Pastores (pahs-TOH-rehs): The drovers positioned along the route who manage the herd and handle separations.
- Cabestros (kah-BEHS-trohs): Steers that run with the herd to keep bulls together. A second group acts as the cleanup team.
- Corralillo (koh-rrah-LEE-yoh): The small holding pen adjacent to the main corrales where the cleanup steers are kept before release.
- Ganaderia (gah-nah-deh-REE-ah): A bull-breeding ranch. Each ganaderia provides six bulls for one morning of the encierro.
Frequently Asked Questions
What is a suelto?
A suelto is a bull that has separated from the herd during the encierro. Without the group instinct to follow, it becomes unpredictable and reactive.
What causes a bull to separate?
The most common causes are falls on the cobblestone surface (especially at turns) and human interference, such as a runner touching or provoking the bull.
What should a runner do if a suelto is nearby?
Run. Stay on your feet and move as fast as you can away from the bull. Do not freeze, do not try to climb over the barrier, and do not crowd around the animal. Leave it to the pastores.
Are some bull breeds more likely to produce a suelto?
Herd behavior varies by ganaderia. Some ranches produce bulls that stay tightly grouped, while others are more prone to separations. Experienced runners check which ranch is providing the bulls each morning.
Run with Preparation, Not Assumptions
A suelto can happen on any morning and at any point along the route. Understanding what causes one, how to recognize one, and what to do when it happens is part of the preparation that separates informed runners from bystanders. Our team covers suelto scenarios and spatial awareness as part of every tour. Book a tour with Encierro and learn to read the encierro before you step into the street.