The power of interspecific sociality: how humans provide social buffering for horses.
Abstract: In this study, we assessed the interspecific "social buffering effect" of humans on horses, exploring how human presence influences stress responses in horses in an unfamiliar environment using the "isolation paradigm." We examined nine Haflinger horses under two counterbalanced conditions: with a passive human stranger (social condition) or alone (isolation condition). Stress responses were assessed through cortisol measurements, heart rate monitoring, and behavioral observations. While cortisol levels significantly increased in both conditions, with no notable differences before and after the tests, heart rate data revealed a different pattern. Results indicated that stress generally decreased in both scenarios, impacting heart rate. Initially, during the first five minutes, heart rate was significantly higher in the social condition compared to isolation, but this trend reversed in the following intervals, with heart rate significantly decreasing as interaction with the stranger increased. Positive interaction between time and stranger-directed behaviors suggested the stranger's influence on heart rate strengthened over time. Overall, these finding suggest that while cortisol data did not reflect a social buffering effect, other metrics indicated that human presence effectively reduced stress in horses after a brief adjustment period, supporting the hypothesis that horses can benefit from human presence during stress, after a short adaptation time. This study highlights the complex nature of stress responses in horses and the potential role of humans as social buffers in interspecific contexts.
© 2025. The Author(s).
Publication Date: 2025-03-12 PubMed ID: 40072705PubMed Central: PMC11903558DOI: 10.1007/s10071-025-01942-5Google Scholar: Lookup
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Summary
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The research article investigates the effect of human presence on stress levels of horses when placed in an unfamiliar environment. The findings suggest that, after an initial adjustment period, human presence reduces stress in horses, highlighting the potential role of humans as “social buffers” in such contexts.
Research Methodology
In this study, nine Haflinger horses were used to examine the impact of human presence on stress levels in unfamiliar environments. The experimental design included two scenarios:
- In the first scenario, the horses were exposed to an unfamiliar environment with a passive human stranger (referred to as the ‘social condition’ in the study).
- In the second scenario, the horses were left alone in the unfamiliar environment (referred to as the ‘isolation condition’ in the study).
Assessing Stress Levels
Stress levels in horses can be tracked and assessed through various metrics. In this study, the researchers used the following methods:
- Cortisol measurements: Cortisol is a hormone that is naturally produced by the body in response to stress. By measuring the amount of cortisol in a horse’s system, the researchers could gain a fairly accurate picture of the animal’s stress levels.
- Heart rate monitoring: During stressful situations, the heart rate of the animal tends to increase. The researchers monitored the horses’ heart rates to assess their stress levels in both conditions.
- Behavioral observations: In addition to physiological metrics, the researchers also observed the horses’ behaviors in response to the two conditions.
Research Findings
Upon evaluation, the researchers found that while cortisol levels significantly increased in both the social and isolation conditions, heart rate data painted a different picture. Initially, during the first five minutes of the test, heart rate was significantly higher when the horses were in the presence of a strange human. However, this trend was soon reversed, with heart rates displaying a significant decrease as time wore on and interaction with the stranger increased. According to the researchers, these findings suggest that while cortisol data may not reflect a social buffering effect from human presence, the reduction in heart rate and changing behaviors over time could. The researchers posit that horses might benefit from human presence during stressful situations, necessitating only a short adjustment period.
Conclusion
The study concluded that the human presence effectively reduces stress in horses after a brief adjustment period, supporting the idea that humans can work as ‘social buffers’ for horses in unfamiliar or stressful situations. The research draws attention to the complex nature of stress responses in horses, emphasizing the importance of integrating multiple assessment methods to gain a comprehensive understanding of the phenomenon.
Cite This Article
APA
Di Lucrezia A, Scandurra A, Lotito D, Iervolino V, D'Aniello B, Mastellone V, Lombardi P, Pinelli C.
(2025).
The power of interspecific sociality: how humans provide social buffering for horses.
Anim Cogn, 28(1), 20.
https://doi.org/10.1007/s10071-025-01942-5 Publication
Researcher Affiliations
- Department of Biology, University of Naples Federico II, 80126, Naples, Italy.
- Department of Biology, University of Naples Federico II, 80126, Naples, Italy.
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, 80137, Naples, Italy.
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, 80137, Naples, Italy.
- Department of Biology, University of Naples Federico II, 80126, Naples, Italy. biagio.daniello@unina.it.
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, 80137, Naples, Italy.
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, 80137, Naples, Italy.
- Department of Environmental, Biological and Pharmaceutical Sciences & Technologies, University of Campania Luigi Vanvitelli, 81100, Caserta, Italy.
MeSH Terms
- Animals
- Horses / physiology
- Horses / psychology
- Hydrocortisone
- Heart Rate
- Humans
- Male
- Female
- Stress, Psychological
- Social Behavior
- Behavior, Animal
- Social Isolation
Conflict of Interest Statement
Declarations. Ethical approval: The experimental procedure was conducted in compliance with ethical standards and was approved by the Ethical Committee for Animal Experimental Procedures (CESA) of the University of Naples Federico II. The research observes the principles outlined in the Declaration of Helsinki and adhered to all relevant international, national, and institutional guidelines for the care and use of animals. Competing interests: The authors declare no competing interests.
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