The Misunderstood Carriage Horses of Mérida. Part II

This article continues the analysis begun in Part I, where we addressed social perception regarding the use of animals and the real physical capacities of horses. In this second part, we present the results of scientific studies conducted on Mérida’s carriage horses, focusing on their daily work, behavior, and resting conditions.  

Dr. Pedro González, DVM Marcela Navarrete

How Demanding Is Carriage Work for Mérida’s Horses?

To answer with data rather than perceptions, we analyzed the routes, working hours, and environmental conditions under which the horses work during the rainy season (1). Using GPS, 33 horses were monitored, recording distances traveled, duration of each trip, rest periods, and weather conditions.

We found that each route measures 5 kilometers and lasts an average of 47 minutes. Some horses completed a maximum of six trips per day, totaling close to five hours of work, with rest periods ranging from one to eight hours between trips. Additionally, they worked two consecutive days and rested on the third. The total load—including the weight of the carriage, the driver, and passengers—was around 700 kilograms, well below the pulling capacity (up to 5,000 kilograms) that a horse of these characteristics can achieve.

During work, no water or food was offered, as hydration and feeding were provided afterward at the properties where they rested. To protect them from the sun, trees or umbrellas were used, and there was an internal regulation limiting the number of daily trips. In terms of exertion, the observed workdays and distances remained within parameters considered safe.

We proposed small management adjustments, particularly regarding hydration, since offering small amounts of fresh water at regular intervals could be more appropriate, especially in hot climates such as Mérida’s. Under the observed conditions, the work of carriage horses remains within normal physiological limits and does not represent a risk to their welfare.

Do They Show Signs of Stress or Suffering During Work?

Beyond measuring distances or weights, it was necessary to determine whether the animals showed signs of discomfort, stress, or pain during their workday. To do so, we recorded and analyzed the behavior of 24 horses while they were pulling their carriages (2).

Over three months, we observed 66 routes, each approximately 5 kilometers long. These took place between 6:00 p.m. and 8:00 p.m., with an ambient temperature of 35 °C and 44% humidity. We specifically evaluated five behaviors that may indicate discomfort: repeated head tossing, biting at the air or reins, pawing the ground, lameness, and abnormal vocalizations.

As a result, we found that no horse produced abnormal vocalizations, and no lameness was observed. Most horses worked without showing signs of discomfort. The only recorded behavior was head tossing, observed in 25% of the routes (note: not 25% of the horses), indicating mild discomfort. This behavior mainly appeared when horses were standing still waiting before beginning the route.

Such head movement is a natural response to immobility or impatience (they get bored) and is also observed in stabled horses. Overall, the low frequency of discomfort-related behaviors indicates that the carriage horses of Mérida we studied are adapted to their work and maintain stable physical and emotional conditions.

Of course, everything can be improved. In this study, we recommended avoiding keeping horses “parked” without movement for more than one hour—that is, giving them opportunities to move, walk, and relax.

How Do Horses Rest After a Day of Work?

Observing how they rest is just as important as observing how they work. With this in mind, between January and March 2021 we analyzed the conditions of the places where they sleep, following recommendations from the World Organisation for Animal Health (OIE/WOAH).

We evaluated available space, ventilation, cleanliness, roof coverage, and visual contact with other horses—an important aspect since horses are highly social animals. Their general health was assessed through a complete veterinary examination evaluating 40 physical characteristics. We also analyzed facial expressions over eight continuous nighttime hours, taking thousands of automatic photographs using hidden cameras.

For this study, we evaluated nine active carriage horses, all assessed after a working day—not on their rest day (3).

Results showed that most horses presented excellent physical condition and good resting spaces: spacious, clean, and well-ventilated. All horses were able to move freely, lie down, and maintain visual contact with companions—essential elements for their welfare. Only minor areas for improvement were identified, such as some damp flooring or areas with less shade, none of which compromised their comfort.

Facial expressions were classified into three categories: positive, neutral, and negative. On average per hour, fifteen neutral expressions were recorded, six positive, and only two negative expressions associated with agonistic behavior. Agonism—or mild threats between horses—is normal behavior in a social species.

Facial gestures associated with pain, such as tension or tightened lips, were practically nonexistent. Instead, relaxed ears and calm postures were the most frequent signs, indicating rest and relaxation. Facial expressions showed normal movements during sleep and did not reflect pain or discomfort, suggesting that the horses rest adequately and do not present signs of accumulated stress.

Final Reflection on Their Level of Care

Horses used for carriage pulling in Mérida often receive more frequent veterinary checkups, more structured rest schedules, and more detailed care than many urban pets—yet many people and tourists are unaware of this.

Studies on working equines indicate that healthy body condition, positive human-animal interactions, and veterinary supervision are common elements in their management (4). Likewise, equine welfare literature recognizes that when animals have access to free movement, social companionship, and an appropriate diet—conditions present in many urban working protocols—their mental and physical health improves significantly (5).

This combination of systematic care means that, in some aspects, carriage horses may be better supervised than companion animals that do not receive that level of oversight.

None of the authors of this document have been paid by any entity related to Mérida’s carriage horses, nor by the City Council nor any other government institution.

Read the first part here: The Misunderstood Carriage Horses of Mérida. Part I

Editorial note: Image generated for illustrative purposes to provide context. It does not represent a specific horse or carriage evaluated in the cited studies.

References

Tello Pasos et al. 2020b. Journal of Equine Veterinary Science. https://doi.org/10.1016/j.jevs.2020.102966

Tello Pasos & González Pech 2022. Journal of Veterinary Behavior. https://doi.org/10.1016/j.jveb.2022.06.003

Tello Pasos et al. 2023. Journal of Veterinary Behavior. https://doi.org/10.1016/j.jveb.2022.11.006

Romero et al. 2022. Frontiers in Veterinary Science. https://doi.org/10.3389/fvets.2022.1031192

Krueger & Düpjan 2021. Animals. https://doi.org/10.3390/ani11061798